Birth Order Effect Research Articles

Birth Order and Family Size of UK Biobank Subjects Identified as Asexual, Bisexual, Heterosexual, or Homosexual According to Self-Reported Sexual Histories.

This study used a recently developed statistical technique to investigate the relations between various elements of a subject's family background and the odds of that subject reporting a sexual history indicative of a minority sexual orientation. The subjects were 78,983 men and 92,150 women who completed relevant questionnaire items in the UK Biobank, a large-scale biomedical database of volunteers aged 40-69 years. The men were divided into three sexual minority groups-homosexual, bisexual, and asexual-and a comparison group of heterosexual men. The same was done for the women. The analytic procedure consisted of logistic regressions specifically designed to disentangle the effects of birth order and family size. The results showed that older brothers increased the odds of homosexuality in both men and women, and that older sisters increased the odds in men. In contrast, neither older brothers or older sisters affected the odds of bisexuality or asexuality in men or in women. These results suggest that birth order effects may be specific to homosexuality and not common to all minority orientations. The only family size finding was the negative association between family size and the odds of asexuality in both men and women. The outcomes of this study indicate that the maternal immune hypothesis, which was advanced to explain the relation between older brothers and homosexuality in later-born males, might have to be abandoned or else expanded to explain the findings concerning females. A few such modifications are considered.

Investigation of the effect of psychological birthorder on perceived parental attitudes and early maladaptive schemas in adults

Aims: The aim of this study is to examine the effect of psychological birth order on perceived parental attitudes and early maladaptive schemas. Methods: In this study, the Psychological Birth Order Inventory, Perceived Parental Attitudes Scale-Child Form, and Young’s Schema Scale were used. The sample consisted of 189 women and 102 men. Relational and predictive analyses were conducted regarding birth order, psychological birth order, perceived parental attitudes, and schema domains. Results: There was a moderate positive relationship between the sibling rank of the women who participated in the study and the emotional deprivation schema area. For female participants, being the middle child was found to have a moderately positive relationship with emotional deprivation, dependence, pessimism, and defectiveness schemas. A weak positive relationship was found between being the middle child and emotional warmth maternal attitude, overprotective mother/father attitude, and rejecting father attitude scores. Conclusion: The study concluded that there is a significant relationship between psychological birth.order and perceived parental attitudes as well as early maladaptive schemas.

Are economic preferences shaped by the family context? The relation of birth order and siblings’ gender composition to economic preferences

The formation of economic preferences in childhood and adolescence has long-term consequences for life outcomes. We study in an experiment how both birth order and siblings’ gender composition are related to risk, time, and social preferences. We find that second-born children are typically less patient, more risk-tolerant, and more trusting. However, siblings’ gender composition interacts importantly with birth order effects. Second-born children are more risk-taking only with same-gender siblings. In mixed-gender environments, children seem to identify with the gender stereotype that boys are much more willing to take risks than girls, irrespective of birth order. For trust and trustworthiness, birth order effects are larger with mixed-gender siblings. Only for patience, siblings’ gender composition does not matter.

Birth order and intrahousehold allocation of food: Unequal allocation for unwanted children

Background: Food allocation is a fundamental aspect within households, seemingly capable of being distributed evenly among household members, especially among siblings. However, several factors can lead to differences in food allocation among siblings. Method: Using data from IFLS 4 and 5, with food variety as a proxy for food allocation, this study examines two influential factors on food allocation: birth order and imperfect fertility control status. Additionally, this study attempts to elucidate the mechanism of the birth order effect using the aforementioned imperfect fertility control status. FIndings: The findings of this study reveal a negative effect of birth order on household food allocation. Moreover, children with undesired status or belonging to families with undesired status due to imperfect fertility control tend to have lower food variety. Conclusion: However, this study cannot causally explain the mechanism behind the negative effect of birth order through imperfect fertility control status. Novelty/Originality of this article: This study analyzes the effects of birth order and fertility control status on household food allocation, finding adverse effects of birth order and unwanted status on food variation. As a novelty, this study proposes the development of a family-based nutrition intervention program that considers intra-household dynamics, aiming to reduce the gap in food allocation between siblings and improve children's overall nutritional status.

Examining the Effect of Birth Order on Neuroticism and Extraversion among Adolescents and Young Adults

This study investigates the influence of birth order on personality traits, specifically Neuroticism and Extraversion, among adolescents and young adults. A total of 120 participants aged between 14-25 years completed a survey distribution via Google Forms. The sample was evenly split into two groups: Elder children (First-born) and Younger children (Last-born), each comprising 60 individuals. The personality traits were assessed using Neuroticism and extraversion subscales of the Neo-Five Factor Inventory (NEO-FFI, Costa & McCrae, 1992). Data analysis involved the use of a two-sample Kolmogorov-Smirnov (K-S) test to compare the distribution of Neuroticism and Extraversion scores between the two birth groups. The results indicate that there is no statistically significant difference in the distribution of Neuroticism and Extraversion traits between elder and younger children. These findings contribute to understanding how birth order is not the sole influence on neuroticism and extraversion among adolescents and young adults.

Examining the Fraternal Birth Order Effect and Sexual Orientation: Insights from an East European Population

The development of human sexual orientation remains a complex and multifaceted subject. It is often studied but its origins continue to elude us. In this preregistered study, our primary objective was to demonstrate the fraternal birth order effect (FBOE), which assumes a higher prevalence of older brothers in gay men than in their straight counterparts and which has also been recently recorded in lesbian women. Our second aim was to explore any potential impact of the FBOE on anal-erotic role orientation (AERO), both in gay and straight men. Our study sample included 693 gay men, 843 straight men, 265 lesbian women, and 331 straight women from Czechia and Slovakia. Employing a conventionally parameterized logistic regression model, we substantiated the FBOE among both gay men (OR = 1.35 for maternal older brothers) and lesbian women (OR = 1.71). These outcomes were confirmed by a more nuanced parameterization recently proposed by Blanchard (2022). Nonmaternal older brothers did not exhibit a significant influence on their younger brothers’ sexual orientation. Contrary to some earlier reports, however, our data did not establish the FBOE as exclusive to gay men with the receptive AERO. Furthermore, our observations indicated a lower offspring count for mothers of gay men compared to mothers of straight men. Emphasizing the positive FBOE outcomes, we acknowledge the need for caution regarding the various options that can be used to estimate the familial influences on sexual orientation.

Differences in caregiver and child factors within families of autistic youth across birth order groups

BackgroundResearch has highlighted the ways that birth order relates to autism spectrum disorder (ASD) prevalence rates. However, little research has focused on how birth order relates to the wellbeing of the family once a child is diagnosed with ASD. Additionally, many family factors (such as measures of parental wellbeing) and elements of child emotional/behavioral symptoms have not yet been investigated when evaluating the potential effects of birth order. The current study aimed to investigate how family birth order may impact caregiver reporting of parental wellbeing/competency and child symptoms. MethodThree groups were created based on caregivers (N = 155) who have (1) a first-born child with ASD and then child(ren) without ASD, (2) child(ren) without ASD and then a child with ASD, and (3) an only child with ASD. Caregivers completed questionnaires measuring family resources, child symptoms, and parental factors. ResultsDespite comparable ratings on family resources and ASD severity, significant differences based on birth order emerged. Having one or multiple children without ASD before having a child with ASD may enhance feelings of satisfaction and competency as a parent. Parents with an only child with ASD also reported higher ratings of competency, had significantly less ASD knowledge, and demonstrated a significant negative correlation between efficacy and knowledge. ConclusionFamilies with an only child with ASD may require further support to augment their knowledge of ASD. Caregivers who have a first-born child with ASD may benefit from interventions focusing on their feelings of parental competency.

Impact of birth order on risk-taking: Evidence from China.

Evidence about impact of birth order on risk-taking is mostly from the Western cultural contexts, and the findings are contradictory. Scant attention has been devoted to the impact of birth order on risk-taking in East Asian societies influenced by Confucian culture. In this study, we investigated how birth order impacts adult risk-taking using a representative Chinese sample (N = 12,756). The results revealed that the effect of birth order on Chinese risk-taking did not exhibit a linear trend, either when the birth order was coded using the original birth rank or when coded as firstborns, middleborns and lastborns. However, this study found that laterborns, as a whole, were more likely to take risks than firstborns. In addition, there was a quadratic trend inherent in the birth order effect on risk-taking, showing that middleborns were more likely to take risks than firstborns or lastborns. Furthermore, we found that the birth order effects on risk-taking were not affected by individuals' age, birth spacing and family size. Additional analyses also demonstrated the robustness of these results. Our findings established a small but meaningful association between birth order and risk-taking in a Confucian-influenced society.

Changing Effects of Birth Order on Education Over Time: Evidence From Cambodia

Despite the vast literature on birth-order effects in developing countries, there has been little research on their long-term changes. This study uses three population censuses of Cambodia to investigate how birth order affects educational attainments and how its effects changed over time. We estimate regressions with family fixed effects and cohort fixed effects, and present four findings. First, later-born children are less likely to enroll in primary school and gain literacy skills, and end up with fewer years of schooling than first-born children. Second, controlling for gender differences in education, we find smaller birth-order effects for girls. Third, there is a strong relationship between the gender composition of siblings and birth-order effects. Finally, not only have these birth-order effects attenuated over time but the relationship between the gender composition of siblings and birth-order effects has also changed. In the 1998 census, if the firstborn child is male, his sisters’ educational outcomes are influenced more by their birth order compared with his brothers. In contrast, in the 2019 census, if the firstborn child is male, his sisters' educational outcomes are less susceptible to birth-order effects compared with his brothers. Our findings indicate gendered economic disparities within households and their long-term changes.

Testing Fraternal Birth Order Effects and Antagonistic Effects for Homosexual Men: Power Comparison of Various Methods.

Research on the biological determinants of male homosexual preference has long realized that the older brother effect (FBOE, i.e., a higher fraternal birth rank of homosexuals) and the antagonist effect (AE, i.e., more fertile women have a higher chance of having a homosexual son) can both generate family data where homosexual men have more siblings and more older siblings than heterosexual men. Various statistical approaches were proposed in the recent literature to evaluate whether the action of FBOE or AE could be discriminated from empirical data, by controlling for the other effect. Here, we used simulated data to formally compare all the approaches that we could find in the relevant literature for their ability to reject the null hypothesis in the presence of a specified alternative hypothesis (tests based on regression, Bayesian modeling, or contingency tables). When testing for the FBOE, the relative performance of the different tests was different depending on the specific function generating the older brother effect. Even if no tests were found to always perform better than the others, some tests performed systematically poorly, and some tests displayed a systematic high rate of type-I error. For testing the AE, the relative performance of the tests was generally not changed across all parameter values assayed, providing a clear ranking of the various proposed approaches. Pros and cons for each candidate test are discussed, taking into consideration power and the rate of type-I error but also practicability, the possibility to control for confounding variables, and to consider alternative hypotheses.

Human Capital Investments and Family Size in Italy: IV Estimates Using Twin Births as an Instrument

Abstract Human capital investments at an early age appear crucial for individual outcomes. Family size might affect these investments influencing parental time and economic resources invested in children’s education. This feature is related to the children quantity-quality trade-off proposed by Becker that has been investigated only for a few countries because of data limitations. We investigate this issue for Italy – even in the absence of Census data relating family of origin to children’s educational outcomes – using many waves of the Survey on Household Income and Wealth of the Bank of Italy and focusing on the educational attainments of 19–23 years old. We use twin births as an instrumental variable to identify exogenous variations in family size. In contrast with the results from other developed countries, we find a significant negative effect of family size on children’s education, probably related to the low quality of education in some regions of the country and to the poor public assistance of families with children. We show that these findings are robust to a number of checks. The effects appear stronger for women, Southern regions, low-income families and when spacing between births is limited, suggesting that both time and financial constraints are mechanisms at work. We also find strong birth order effects.

Sibling Birth Order Among Undergraduate University Students and Its Influence on Personality Traits: Some Implications for Education

This cross-sectional survey explores the influence of sibling birth order on university students’ personality traits. The sample consisted of 184, predominantly Chinese, Malaysian undergraduates of a private university in Malaysia. The Big-Five personality questionnaire (John & Benet-Martinez, 1998) was used for data collection, while Confirmatory Factor Analysis (CFA) and path analysis from SEM were used to analyse the data. The CFA results show a significant interrelationship between the traits of extroversion and agreeableness but no significant direct effect of birth order on personality traits. The results are consistent with the previous studies in Malaysia and around the globe and suggest the likelihood of other factors (e.g., social culture and environment) possibly influencing student personality. Subsequent research that employs various Malaysian samples is needed to further test the applicability of Sulloway’s theory in explaining the influence or effect of sibling birth order in Malaysia.

An integrated model: marital effect on adolescent behavioral problems through siblings.

Few studies have simultaneously focused on the effects of marital conflict and marital intimacy on adolescent development, and little is known about the role of sibling relationships. Thus, this study examined the association between marital relationships and adolescent behavioral problems, including depressive symptoms and aggressive behavior. At the same time, we explored the mediating role of sibling hostility and sibling affection and the moderating effect of birth order in multichild families in China. Participants included 842 adolescents (Mage = 12.60, 46.2% boys) from Henan Province. Marital relationship, sibling relationship, birth order, depressive symptoms and aggressive behavior were assessed by a self-administered questionnaire. SEM was then used to examine the role of sibling relationships and birth order in the association between marital relationship and adolescent behavioral problems. Our results showed that marital intimacy was negatively correlated with depressive symptoms and aggressive behavior, while marital conflict was positively correlated with them. Marital intimacy was associated with depressive symptoms and aggressive behavior through both sibling hostility and sibling affection. Marital conflict was indirectly associated with depressive symptoms and aggressive behavior through sibling hostility. In addition, the first-born adolescents were more sensitive to marital intimacy. Given that the occurrence of adolescent behavioral problems is more common in contemporary society, our findings suggest that establishing a more intimate and warmer family atmosphere and promoting positive interactions between siblings may help control adolescent mental health problems.

Birth Order Effects on Education: Insights from Low- and Middle-Income Countries

Birth Order Effects on Education: Insights from Low- and Middle-Income Countries

Multiparity favors same-sex partner preference in male rats

Same-sex partner preference is present in many mammals, including rodents. Several possible causal factors have been proposed for the establishment of this preference. The Fraternal Birth Order effect refers to the observation that older brothers increase the probability of homosexuality in men, but no experiment has analyzed this possibility. In this study, partner preference (tested in a three compartments box) and female and male sexual behavior (studied in a cylindrical arena) were evaluated in young male rats (3 months) born to multiparous mothers that had 4-6 previous gestations and around 12 months of age. Control groups were young male rats born to primiparous young (4 months) or aged (12 months) mothers. In the partner preference test, the males born to multiparous dams spent less time interacting with the receptive female and more time interacting with the sexually active male, and a 39% exhibited same-sex partner preference. This high percentage seems related to multiparity of their mothers and not to maternal age, because the males born to primiparous aged females (12 months) showed a similar low proportion of same-sex partner preference than the males born to young (4 months) primiparous females (4%). In the sexual behavior tests, no male born of a multiparous dam and with same-sex preference ejaculated and 54% displayed proceptivity and lordosis. Present results suggest that the fraternal birth order effect may occur also in rats.

Male androphilia, fraternal birth order, and female fecundity in Samoa: A 10-y retrospective.

Two separate but related literatures have examined familial correlates of male androphilia (i.e., sexual attraction and arousal to masculine adult males). The fraternal birth order effect (FBOE) is a widely established finding that each biological older brother a male has increased the probability of androphilia 20-35% above baseline rates. Other family demographic variables, such as reproduction by mothers, maternal aunts, and grandmothers, have been used to test evolutionary hypotheses that sexually antagonistic genes lead to androphilia among males, lowering or eliminating reproduction, which is offset by greater reproductive output among their female relatives. These proposed female fecundity effects (FFEs), and the FBOE, have historically been treated as separate yet complementary ways to understand the development and evolution of male androphilia. However, this approach ignores a vital confound within the data. The high overall reproductive output indicative of an FFE results in similar statistical patterns as the FBOE, wherein women with high reproductive output subsequently produce later-born androphilic sons. Thus, examination of the FBOE requires analytic approaches capable of controlling for the FFE, and vice-versa. Here, we present data simultaneously examining the FBOE and FFE for male androphilia in a large dataset collected in Samoa across 10 y of fieldwork, which only shows evidence of the FBOE.

Inferiority and Superiority Complex: Examination in Terms of Gender, Birth Order and Psychological Symptoms

Inferiority and superiority complex are personality structures that point to unhealthy development in Adlerian theory. In this study, the aim was to examine inferiority and superiority complex in terms of socio-demographic characteristics of adult individuals, and to determine the predictive relationships between psychological symptoms and inferiority and superiority complex. A total of 361 (205 females, 156 males) adults between the ages of 18 and 62, reached through the convenient sampling method, participated in the study. Data were collected through the Turkish Version of the Adlerian Inferiority and Superiority Complex Shortened Scales, the Symptom Check List, and the Personal Information Form. In the study, it was found that the main effects of gender and birth order were significant in inferiority complex, while the main effect of birth order was significant in superiority complex. Gender main effect for superiority complex and gender-birth order interaction effect for both complexes were not significant. In addition, it was determined that psychological symptoms were a significant predictor of inferiority complex, but not a significant predictor of superiority complex.

Birth-order effects on risk taking are limited to the family environment.

Why is the empirical evidence for birth-order effects on human psychology so inconsistent? In contrast to the influential view that competitive dynamics among siblings permanently shape a person's personality, we find evidence that these effects are limited to the family environment. We tested this context-specific learning hypothesis in the domain of risk taking, using two large survey datasets from Germany (SOEP, n = 19,994) and the United States (NLSCYA, n = 29,627) to examine birth-order effects on risk-taking propensity across a wide age range. Specification-curve analyses of a sample of 49,621 observations showed that birth-order effects are prevalent in children aged 10-13 years, but that they decline with age and disappear by middle adulthood. The methodological approach shows the effect is robust. We thus replicate and extend previous work in which we showed no birth-order effects on adult risk taking. We conclude that family dynamics cause birth-order effects on risk taking but that these effects fade as siblings transition out of the home.

Cognitive Abnormalities in Juveniles Suffering from Drug Abuse

Objectives: The study aimed to identify cognitive distortions among juvenile drug abusers in Jordan. Methods: The sample consisted of (55) male juveniles in short-term detention at Al-Zohour Security Center, using the available method. The cognitive Distortions scale was applied to them after extracting its validity and reliability. Results: The results indicated that the level of cognitive distortions was moderate and that cognitive distortion “minimization and maximization” came at a high level while “reading what was in the minds of others” came last at a low level. The results also showed no significant differences attributed to the effect of the family’s monthly income in all areas except in excessive generalization” in favor of those with monthly income from 500 to 1000 JD. There were no significant differences due to the effect of birth order. Conclusion: It was found that cognitive distortions exist among juveniles who are drug abusers to a moderate degree, and this means that these juveniles have a problem regarding the use of these cognitive distortions. These individuals need to know the reality of these distortions and the extent of their impact on its lives. The study recommends designing and implementing counseling programs to reduce these distortions thus reducing the use of drugs, and replacing them with effective coping strategies in dealing with life stressors.

The Effect of Siblings on the Academic Self-efficacy and Self-educational Expectations of University Students

With the introduction of Chinas one-child policy in the 1970s, much research was done to study only children on their well-being, personality, and academic achievement. However, few studies have focused on how they differ from non-only children regarding academic self-efficacy and self-educational expectations and the results have not come to an agreement. Thus, this study targeted the undergraduates in mainland China and those who come from the mainland but studying in Hong Kong. An online questionnaire was published and a total of 140 valid responses were collected. MANOVAs and multiple linear regression models were established in order to investigate the effect of singleton status, birth order, and gender of siblings on university students academic self-efficacy and self-educational expectations. The results showed that the singleton status, birth order, and gender of siblings had no significant influence on both academic self-efficacy and self-educational expectations, and a significant interaction between birth order and gender of siblings on the score of academic self-efficacy. This study adds to the recent status of the academic self-efficacy and self-educational expectations among undergraduates studying in Mainland and Hong Kong, only children and non-only children. However, due to insufficient sample size, gender and current years of study of students were not included in the comparison, which needs to be further investigated.