Influence of Older Siblings on Initiation of Sexual Intercourse

Abstract

This study uses data from the 1993 Philadelphia Teen Survey (via telephone) of 2080 adolescents and their parents (75% completion rate) to examine the factors affecting early initiation of sexual intercourse that are associated with sibling influence and gender after controlling for parental behavior and attitudes about adolescent sexuality. Data were gathered on two teenagers living in the same household in 218 cases and were analyzed for 183 pairs. The report also contains an introductory review of the literature on the role of older siblings as orientational others and on the effect of the gender of siblings. The model tested in the study predicts that 1) the normative beliefs of older siblings influence younger siblings 2) the sex behavior of older siblings influences younger siblings 3) the sex behaviors and normative beliefs in the older siblings reference groups influence younger siblings 4) the effects remain after parental effects are controlled 5) the influence of an older sibling is greater when siblings are the same gender 6) the influence of older siblings increases when both siblings are female and 7) older brothers have the most influence on younger brothers and/or sisters. Statistical analysis confirmed that the older siblings influence the sex behavior of younger siblings through a process in which younger siblings compare themselves with older siblings. It was also found that parental effects have a stronger impact than sibling effects on the odds of a younger sibling being a non-virgin. Older brothers however influence the sex behavior of younger siblings of both genders (stronger for younger brothers) and also influence use of birth control during first intercourse. Older sisters influence younger siblings only by connecting them with new reference groups. Further research is needed to explore the influence of various characteristics of the sibling relationship and sexual activity.