Offspring Intelligence Research Articles

Prenatal cannabis use and its impact on offspring neuro-behavioural outcomes: A systematic review.

Cannabis is a widely used substance in pregnancy, yet there is a paucity of literature addressing the neuro-behavioural consequences for prenatally exposed children. Our systematic review synthesizes currently available data for the impact of prenatal cannabis use on offspring intelligence and cognitive functioning. MEDLINE, EMBASE, PsychINFO, CINAHL, and Clinicaltrials.gov were searched. Observational studies comparing prenatal cannabis use to controls were included. Offspring neuro-behavioural outcomes were grouped in prespecified domains of (1) intelligence and (2) cognitive functioning. Random-effect models were performed for meta-analyses when at least three studies reported the same outcome. All others were summarized qualitatively. GRADE (Grading of Recommendations, Assessment, Development and Evaluations) framework was used to assess evidence certainty. Of the 1982 reviewed studies (n = 523,107 patients), 28 were included. Significant heterogeneity and cohort redundancy limited meta-analysis. Very low-quality evidence from pooled analyses showed no significant associations between prenatal cannabis exposure and attention [standardized mean difference = -0.27 (95% CI = -0.60 to 0.07)], global intelligence quotient [-0.16 (-0.42 to 0.10)], reading [-0.05 (-0.29 to 0.20)], written comprehension [-0.09 (-0.40 to 0.22)], spelling [-0.04 (-0.26 to 0.17)], and mathematics [-0.01 (-0.15 to 0.13)]. No significant associations were found between prenatal cannabis exposure for all other outcomes. Individual studies reported significant differences between the heavy use groups and non-exposed, although this did not prove to be significant when outcomes were pooled. The current review did not find a clear association between prenatal cannabis use and offspring neuro-behavioural outcomes. However, evidence was low quality and heterogenous. Further prospective investigation is needed to elucidate any potential association between prenatal cannabis use and long-term neuro-developmental outcomes.

A study of emotional intelligence in an Egyptian sample of offspring of patients with schizophrenia

BackgroundEmotional intelligence is usually a construct measured in healthy children, now it may be used for relatives of schizophrenia, and considered as trait marker for schizophrenia. Offspring of parents with schizophrenia are considered children with high familial risk for major mental disorder. The aim of the study is to assess emotional intelligence in a group of off springs of a parent with schizophrenia and compare them to healthy control subjects, and to find possible relation between emotional intelligence in offspring and profile of symptoms in schizophrenic parents.ResultsOffspring of parents with schizophrenia had lower scores of emotional intelligences than their matched controls in emotion perception, self-esteem, low impulsivity and emotion regulation’s subsets of TEIQue-CF. There was correlation between offspring trait emotional intelligence and their parent’s duration of illness. There was no correlation found between schizophrenia severity in the parents and their offspring’s trait emotional intelligence.ConclusionsOffspring of parents with schizophrenia had impaired trait emotional intelligence in some of its facets when compared to normal healthy subjects.

A longitudinal investigation of intellectual functioning in youth at high risk for bipolar and depressive disorders

• Participants were 192 children of mothers with or without a diagnosed mood disorder. • Offspring's intelligence quotients were assessed from childhood to emerging adulthood. • Children of depressed vs healthy mothers had less of an increase in intelligence trajectories. • Cognitive functioning may be protective for male offspring of mood disorder mothers. • Limitations include small sample size and higher socioeconomic status participants.

Outcomes in Pregnant Patients with Subclinical Hypothyroidism and Thyroid Autoimmunity: A Critical Appraisal of Recent Randomized Controlled Trials

The management of subclinical hypothyroidism (SCH) and thyroid autoimmunity (TAI) in pregnancy is still uncertain. Over the years, several scientific societies published guidelines on the management of thyroid dysfunction before, during, and after pregnancy, the most recent ones being published by the American Thyroid Association (ATA) in 2017. This study aimed to review the published literature in the field from 2017 onward to investigate whether new findings can change ATA recommendations. A literature search was conducted in PubMed between March 2017 (date of the publication of the ATA guidelines) and March 2020. The research was restricted to randomized controlled trials (RCTs), having pregnancy-related complications in patients with SCH and TAI as the main focus. A total of 5 RCTs were retrieved, 2 of which investigated pregnant women with SCH and 3 with TAI. Selected studies displayed proofs against treating maternal SCH and hypothyroxinemia because no benefit from LT4 was demonstrated in offspring intelligence quotient and in pregnancy outcomes; moreover, they reported proofs against treating TAI patients because no benefit from LT4 was demonstrated in improving pregnancy rate or live birth rate or reducing miscarriage rate.RCTs published from 2017 to 2020 might have a significant impact on current ATA guidelines. In particular, they suggested that isolated hypothyroxinemia and SCH should not be treated and that considering treatment in antibodypositive women, especially those with TSH of 2.5-4.0 mIU/L, would not be justified; they suggested that infertility and miscarriage rates are not decreased by LT4 treatment in euthyroid antibody-positive women seeking pregnancy.

Associations of Prepregnancy Body Mass Index, Gestational Weight Gain, and Intelligence in Offspring: A Systematic Review and Meta-Analysis

Abstract Objective: Increasing evidences have shown that prepregnancy maternal weight and gestational weight gain (GWG) may associate with offspring's neurodevelopment. However, the effects of prepregnancy maternal overweight, obesity, and excessive GWG on offspring's intelligence remain controversial. This meta-analysis aimed to re-assess the association between prepregnancy body mass index (BMI), GWG, and children's intelligence. Methods: We systematically searched multiple databases, including PubMed, EMBASE, Cochrane Library, and Ovid Medline, from their inception through February 2021. Studies assessing the association between prepregnancy BMI or GWG and children's intelligence were further screened manually before final inclusion. Cohorts that analyzed the association between prepregnancy BMI or GWG and intelligence of offspring were included, and we used the Mantel-Haenszel fixed-effects method to compute the weighted mean difference (WMD) and 95% confidence interval (CI) of each study. Results: A total of 12 articles were included in this systematic review, while six of them in the meta-analysis. There was a significant full-scale IQ reduction in children born from overweight and obese mothers, with WMDs of -3.08 (95% CI: -4.02, -2.14) and -4.91 (95% CI: -6.40, -3.42), respectively. Compared with control group, the WMDs for performance and verbal intelligence quotient (IQ) were decreased in overweight and obesity groups. However, we observed no association between children's full-scale IQ and excessive GWG with WMD of -0.14 (95% CI: -0.92, 0.65). Conclusions: Women's prepregnancy overweight and obesity adversely associate with children's intelligence but no association with excessive GWG. Our study suggests that further researches focusing on the effect of prepregnancy maternal health on offspring's intelligence development are needed.

Intelligence in offspring born to women exposed to intimate partner violence: a population-based cohort study

Background: Intimate partner violence (IPV) is a risk factor for developmental problems in offspring. Despite a high prevalence of IPV in the UK and elsewhere, the longer-term outcomes of offspring born to exposed mothers remain under-researched. Methods: Population-based cohort study. We assessed IPV prevalence by type and timing for 3,153 mother-child pairs with complete data within our study population and examined associations between IPV and offspring IQ. We used multiple-imputation to evaluate bias due to our exclusion of observations with missing covariate data. Results: Nearly one in five mothers reported IPV during the study period, with 17.6% reporting emotional violence and 6.8% reporting physical violence. Taking into account potential confounders, the IQ scores of children born to mothers exposed to physical violence remained lower than those of maternally unexposed children (full-scale IQ = −2.8 points [95%CI −4.9 to −0.7], verbal IQ = −2.2 [95%CI −4.4 to −0.1], performance IQ = −2.7 [95%CI −5.0 to −0.5]) and odds of below-average intelligence (IQ<90) remained increased for full-scale (OR 1.48 [95%CI 1.03 to 2.14] and performance IQ (OR 1.48 [95%CI 1.08 to 2.04]) but not verbal IQ (OR 1.06 [95%CI 0.69 to 1.64]). Most physical violence occurred postnatally, and relative odds were most substantial when mothers were exposed to violence across pre-/perinatal and postnatal study periods (OR performance IQ<90 = 2.97 [95%CI 1.30 to 6.82]). Conclusions: Maternal exposure to physical IPV is associated with lower offspring IQ at age 8. Associations persisted after adjusting for potential confounders and were driven by violence occurring postnatally.

Intelligence in offspring born to women exposed to intimate partner violence: a population-based cohort study.

Background: Intimate partner violence (IPV) is a risk factor for developmental problems in offspring. Despite a high prevalence of IPV in the UK and elsewhere, the longer-term outcomes of offspring born to exposed mothers remain under-researched. Methods: Population-based cohort study. We assessed IPV prevalence by type and timing for 3,153 mother-child pairs with complete data within our study population and examined associations between IPV and offspring IQ. We used multiple-imputation to evaluate bias due to our exclusion of observations with missing covariate data. Results: Nearly one in five mothers reported IPV during the study period, with 17.6% reporting emotional violence and 6.8% reporting physical violence. Taking into account potential confounders, the IQ scores of children born to mothers exposed to physical violence remained lower than those of maternally unexposed children (full-scale IQ = -2.8 points [95%CI -4.9 to -0.7], verbal IQ = -2.2 [95%CI -4.4 to -0.1], performance IQ = -2.7 [95%CI -5.0 to -0.5]) and odds of below-average intelligence (IQ<90) remained increased for full-scale (OR 1.48 [95%CI 1.03 to 2.14] and performance IQ (OR 1.48 [95%CI 1.08 to 2.04]) but not verbal IQ (OR 1.06 [95%CI 0.69 to 1.64]). Most physical violence occurred postnatally, and relative odds were most substantial when mothers were exposed to violence across pre-/perinatal and postnatal study periods (OR performance IQ<90 = 2.97 [95%CI 1.30 to 6.82]). Conclusions: Maternal exposure to physical IPV is associated with lower offspring IQ at age 8. Associations persisted after adjusting for potential confounders and were driven by violence occurring postnatally.

Is Social Inequality in Cognitive Outcomes Increased by Preterm Birth–Related Complications?

The study by Benavente-Fernandez et al1 investigated the association of maternal education as a marker of socioeconomic status (SES) and complications related to very preterm birth, such as chronic lung disease (CLD), intraventricular hemorrhage (IVH), and reduced white matter volume (WMV), with cognitive development in preschool-aged children. The study found that within the very preterm group, maternal education at time of birth was similar in effect size to indicators of brain injury, such as WMV or IVH. In plain language, having a mother with a primary- or secondary-school education, compared with a mother who has a postgraduate education, has the same adverse association with the intelligence of offspring as if the child had experienced severe IVH or CLD. In contrast, maternal education was not found to be associated with motor development. Rather, being small for gestational age and having severe IVH, CLD, or reduced WMV were the best predictors.

Association of Maternal Roux-en-Y Gastric Bypass with Obstetric Outcomes and Fluid Intelligence in Offspring.

The purpose of the study is to assess whether Roux-en-Y gastric bypass (RYGB) prior to pregnancy is associated with fluid intelligence in offspring. Additionally, perinatal and obstetric outcomes, and children nutritional status were evaluated. Singleton births of women who underwent RYGB between 2000 and 2010 (BS) were matched to two control births by maternal age, delivery year, and gender. Control group 1 (CG1) and control group 2 (CG2) included women with a pre-pregnancy body mass index (BMI) < 35kg/m2 and ≥ 35kg/m2, respectively, who had never undergone bariatric surgery. Thirty-two children from each group (n = 96) were analyzed, mostly female (59%) and Caucasian (82%), with a mean age of 7 ± 2years. Their general intelligence scores were similar after adjusting for sociodemographic confounders; family economic class was the strongest predictor (low: β = - 20.57; p < 0.001; middle: β = - 9.34; p = 0.019). Gestational diabetes mellitus (OR 0.06; 95% CI 0.03; 0.35) and hypertensive disorders (OR 0.09; 95% CI 0.01; 0.40) were less frequent in BS than CG2. Post-RYGB pregnancies were associated with lower birth weight (P = 0.021) than controls. Child overweight and obesity was higher (OR 4.59; 95% CI 1.55; 13.61; p = 0.006) in CG2 (78%) than CG1 (44%) and similar to BS (65%). RYGB prior to pregnancy was not associated with fluid intelligence in offspring. Prior RYGB was associated with a lower frequency of gestational diabetes mellitus and hypertensive disorders than in women with a pre-pregnancy BMI ≥ 35kg/m2, as well as with lower birth weight than both control groups.

MATERNAL SENSITIVITY AND PERFORMANCE AND VERBAL INTELLIGENCE IN LATE CHILDHOOD AND ADOLESCENCE

The aim of this study was to investigate the association between maternal sensitivity and offspring intelligence in late childhood and adolescence. Secondary data (N=117) from the Block and Block (2006a, b) 30-year longitudinal study of Californian children, which began in the late 1960s, was used to test the hypothesis that maternal sensitivity in childhood would be predictive of late childhood and adolescent intelligence. Correlational analyses revealed that maternal sensitivity, as judged by raters viewing mother's interactions with their children in a set of four joint structured cognitive tasks when the child was 5 years of age, was associated with verbal and performance IQ test scores when the children were ages 11 and 18. Using hierarchical regression to control for child sex, socioeconomic status, child temperament, child baseline IQ (as measured at age 4), mother's level of education and mother's emotional nurturance, it was found that the maternal sensitivity and child and adolescent IQ association held for verbal, but not performance IQ. Furthermore, a pattern emerged in which the association between maternal sensitivity and verbal IQ was stronger for adolescents with a lower baseline IQ. The results suggest that maternal sensitivity is associated with offspring verbal intelligence and that this association holds when numerous variables are accounted for. Additionally, this association may be stronger for children with lower IQs.

Maternal and offspring intelligence in relation to BMI across childhood and adolescence

ObjectiveThe present study tested the association between both mothers’ and offspring’s intelligence and offspring’s body mass index (BMI) in youth.MethodParticipants were members of the National Longitudinal Survey of Youth 1979 (NLSY-79) Children and Young Adults cohort (n = 11,512) and their biological mothers who were members of the NLSY-79 (n = 4932). Offspring’s IQ was measured with the Peabody Individual Achievement Test (PIAT). Mothers’ IQ was measured with the Armed Forces Qualification Test (AFQT). A series of regression analyses tested the association between IQ and offspring’s BMI by age group, while adjusting for pre-pregnancy BMI and family SES. The analyses were stratified by sex and ethnicity (non-Black and non-Hispanic, Black, and Hispanic).ResultsThe following associations were observed in the fully adjusted analyses. For the non-Blacks and non-Hispanics, a SD increment in mothers’ IQ was negatively associated with daughters’ BMI across all age-groups, ranging from β = −0.12 (95% CI −0.22 to −0.02, p = 0.021) in late childhood, to β = −0.17 (95% C.I. −0.27 to −0.07, p = 0001), in early adolescence and a SD increment in boys’ IQ was positively associated with their BMI in early adolescence β = 0.09 (95% CI 0.01–0.18, p = 0.031). For Blacks, there was a non-linear relationship between mothers’ IQ and daughters’ BMI across childhood and between girls’ IQ and BMI across adolescence. There was a positive association between mothers’ IQ and sons’ BMI in early adolescence (β = 0.17, 95% CI 0.02–0.32, p = 0.030). For Hispanic boys, there was a positive IQ-BMI association in late childhood (β = 0.19, 95% CI 0.05–0.33, p = 0.008) and early adolescence (β = 0.17, 95% CI 0.04–0.31, p = 0.014).ConclusionMothers’ IQ and offspring’s IQ were associated with offspring’s BMI. The relationships varied in direction and strength across ethnicity, age group and sex. Obesity interventions may benefit from acknowledging the heterogeneous influence that intelligence has on childhood BMI.

The Role of Paternal Age in the Prediction of Offspring Intelligence

ABSTRACTRecent evidence suggests that paternal age at birth influences myriad developmental outcomes among children, but few studies have examined the possibility for father's age to influence children's intellectual development among a sample of high-risk families. The authors use data from the Fragile Families and Child Wellbeing Study to examine the association between paternal age at birth among 480 male and 449 female children's verbal IQ scores, as assessed with a version of the Peabody Picture Vocabulary Test at 9 years old. The nonlinear association between paternal age and children's verbal intelligence was also examined. Paternal age at birth appears to have a marginally significant nonlinear relationship with male children's verbal IQ scores, despite controlling for a number of possible confounders associated with both young and advanced paternal age.

Is the association between offspring intelligence and parents' educational attainment influenced by schizophrenia or mood disorder in parents?

Results from twin, family, and adoption studies all suggest that general intelligence is highly heritable. Several studies have shown lower premorbid intelligence in individuals before the onset of both mood disorders and psychosis, as well as in children and adolescents at genetic high risk for developing schizophrenia. Based on these findings, we aim to investigate if the association between educational achievement in parents and intelligence in their offspring is influenced by schizophrenia or mood disorder in parents. In a large population-based sample of young adult male conscripts (n=156,531) the presence of a mental disorder in the parents were associated with significantly lower offspring scores on a test of general intelligence, the Børge Priens Prøve (BPP), and higher educational attainment in parents was significantly associated with higher BPP test scores in offspring. A significant interaction suggested that the positive association between maternal education and offspring intelligence was stronger in offspring of mothers with schizophrenia compared to the control group (p=0.03). The associations between parental education and offspring intelligence are also observed when restricting the sample to conscripts whose parents are diagnosed after 30years of age. In conclusion, findings from this study show a more positive effect of education on offspring intelligence in mothers with schizophrenia compared to mothers from the control group. This effect could have both environmental and genetic explanations.

Fruchtbarkeitsbehandlung beeinträchtigt intellektuelle Entwicklung nicht

Bay B et al. Long-awaited pregnancy: intelligence and academic performance in offspring of infertile parents – a cohort study. Fertil Steril 2016; 106: 1033–1040

Long-awaited pregnancy: intelligence and academic performance in offspring of infertile parents—a cohort study

To study whether fertility treatment, subfertility, or pregnancy planning are related to long-term intellectual development. Cohort study. Not applicable. A total of 5,032 singletons born from 1990 to 1992 in the Aarhus Birth Cohort were followed up to a mean age of 19years. These children were born as a result of fertility treatment (n = 210), had subfertile parents who took more than 12months before conceiving naturally (n = 334), had fertile parents who conceived naturally within 12months (n = 2,661), or had parents who reported the pregnancy as unplanned (n = 1,827). The children were followed up using questionnaires and information from Danish national registers. Parent reported school difficulties at ages 9-11years, register-based school grades at ages 16, 17, and 19years, and conscription intelligence test scores at age 19years. We found no evidence of school difficulties in childhood, impaired school performance in adolescence, or lower intelligence in young adulthood in multivariate analyses adjusted for parental age, educational level, maternal parity, before pregnancy body mass index (BMI), smoking and alcohol intake in pregnancy, cohabitation status, child gender, and age. In the longest follow-up of cognitive development of children conceived after fertility treatment or by subfertile parents conducted so far, this study did not show any association between pregnancy planning, subfertility, or fertility treatment and cognitive ability or academic performance.

Explaining the variable penetrance of CNVs: Parental intelligence modulates expression of intellectual impairment caused by the 22q11.2 deletion.

The role of rare genetic variants, in particular copy number variants (CNVs), in the etiology of neurodevelopmental disorders is becoming increasingly clear. While the list of these disorder-related CNVs continues to lengthen, it has also become clear that in nearly all genetic variants the proportion of carriers who express the associated phenotype is far from 100%. To understand this variable penetrance of CNVs it is important to realize that even the largest CNVs represent only a tiny fraction of the entire genome. Therefore, part of the mechanism underlying the variable penetrance of CNVs is likely the modulatory impact of the rest of the genome. In the present study we used the 22q11DS as a model to examine whether the observed penetrance of intellectual impairment-one of the main phenotypes associated with 22q11DS-is modulated by the intellectual level of their parents, for which we used the parents' highest level of education as a proxy. Our results, based on data observed in 171 children with 22q11DS in the age range of 5-15 years, showed a significant association between estimated parental cognitive level and intelligence in offspring (full scale, verbal and performance IQ), with the largest effect size for verbal IQ. These results suggest that possible mechanisms involved in the variable penetrance observed in CNVs include the impact of genetic background and/or environmental influences. © 2016 Wiley Periodicals, Inc.

Maternal Obesity and Excessive Gestational Weight Gain Are Associated with Components of Child Cognition1–3

Background: Maternal overweight and obesity affect two-thirds of women of childbearing age and may increase the risk of impaired child cognition.Objective: Our objective was to test the hypothesis that high/low gestational weight gain (GWG) and high/low prepregnancy BMI were associated with offspring intelligence quotient (IQ) and executive function at age 10.Methods: Mother–infant dyads (n = 763) enrolled in a birth cohort study were followed from early pregnancy to 10 y postpartum. IQ was assessed by trained examiners with the use of the Stanford Binet Intelligence Scale–4th edition. Executive function was assessed by the number of perseverative errors on the Wisconsin Card Sorting Test and time to complete Part B on the Trail Making Test. Self-reported total GWG was converted to gestational-age–standardized GWG z score. Multivariable linear regression and negative binomial regression were used to estimate independent and joint effects of GWG and BMI on outcomes while adjusting for covariates.Results: At enrollment, the majority of women in the Maternal Health Practices and Child Development cohort were unmarried and unemployed, and more than one-half reported their race as black. The mean ± SD GWG z score was −0.5 ± 1.8, and 27% of women had a pregravid BMI ≥25. The median (IQR) number of perseverative errors was 23 (17, 29), the mean ± SD time on Part B was 103 ± 42.6 s, and 44% of children had a low average IQ (≤89). Maternal obesity was associated with 3.2 lower IQ points (95% CI: −5.6, −0.8) and a slower time to complete the executive function scale Part B (adjusted β: 12.7 s; 95% CI: 2.8, 23 s) compared with offspring of normal-weight mothers. Offspring of mothers whose GWG was >+1 SD, compared with −1 to +1 SD, performed 15 s slower on the executive function task (95% CI: 1.8, 28 s). There was no association between GWG z score and offspring composite IQ score (adjusted β: −0.32; 95% CI: −0.72, 0.10). Prepregnancy BMI did not modify these associationsConclusions: Although GWG may be important for executive function, maternal BMI has a stronger relation than GWG to both offspring intelligence and executive function. Our findings contribute to evidence linking maternal obesity to long-term child outcomes.

Fertility treatment and child intelligence, attention, and executive functions in 5-year-old singletons: a cohort study.

To assess the association of fertility treatment and subfertility with offspring intelligence, attention, and executive functions in 5-year-old singletons. Follow-up study. Denmark 2003-2008. A cohort of 1782 children sampled from the Danish National Birth Cohort. The children were tested with a neuropsychological battery at age five. In addition to tests of intelligence, attention and executive functions, the follow up included extensive information on important covariates. The analyses were conducted using multiple linear regression and adjusted for parental educational level, maternal intelligence, age, parity, body mass index, smoking in pregnancy, alcohol consumption in pregnancy and child gender, child age, and examiner. Wechsler Preschool and Primary Scale of Intelligence-Revised, the Test of Everyday Attention for Children at Five, and the Behavior Rating Inventory of Executive Functions scores. A consistent pattern of nonsignificantly lower scores were only observed for intelligence and executive functions in children born after fertility treatment or by subfertile parents when the results were unadjusted for maternal intelligence and parental educational level. When adjusted for these and other covariates, there were no significant mean differences in intelligence (mean difference -2.8, 95% CI -7.8, 2.2), overall attention (-0.1, 95% CI -0.6, 0.3), or parent-rated executive functions (-0.1, 95% CI -3.0, 2.9) between children born after spontaneous conception and children born to parents conceiving after fertility treatment. Similarly, there were no significant mean differences in intelligence (mean difference 0.6, 95% CI -2.2, 3.4), overall attention (0.1, 95% CI -0.2, 0.4), or parent-rated executive functions (1.0, 95% CI -1.8, 3.7) between children born after spontaneous conception and children born to subfertile parents waiting more than 12months before conceiving naturally. This study suggests that parental subfertility and fertility treatment are unrelated to offspring intelligence, attention and executive functions.

Correction: The Effect of Paternal Age on Offspring Intelligence and Personality when Controlling for Paternal Trait Level

Correction: The Effect of Paternal Age on Offspring Intelligence and Personality when Controlling for Paternal Trait Level

The Effect of Paternal Age on Offspring Intelligence and Personality when Controlling for Parental Trait Levels

Paternal age at conception has been found to predict the number of new genetic mutations. We examined the effect of father’s age at birth on offspring intelligence, head circumference and personality traits. Using the Minnesota Twin Family Study sample we tested paternal age effects while controlling for parents’ trait levels measured with the same precision as offspring’s. From evolutionary genetic considerations we predicted a negative effect of paternal age on offspring intelligence, but not on other traits. Controlling for parental intelligence (IQ) had the effect of turning an initially positive association non-significantly negative. We found paternal age effects on offspring IQ and Multidimensional Personality Questionnaire Absorption, but they were not robustly significant, nor replicable with additional covariates. No other noteworthy effects were found. Parents’ intelligence and personality correlated with their ages at twin birth, which may have obscured a small negative effect of advanced paternal age (<1% of variance explained) on intelligence. We discuss future avenues for studies of paternal age effects and suggest that stronger research designs are needed to rule out confounding factors involving birth order and the Flynn effect.