Examining the Fraternal Birth Order Effect and Sexual Orientation: Insights from an East European Population
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View abstract on PubMed
Summary
This summary is machine-generated.The fraternal birth order effect (FBOE) was confirmed in gay men and lesbian women, showing older brothers increase likelihood of same-sex orientation. This study also found no link between FBOE and anal-erotic role orientation.
Area Of Science
- Human sexuality research
- Developmental psychology
- Behavioral genetics
Background
- The origins of human sexual orientation are complex and not fully understood.
- The fraternal birth order effect (FBOE) suggests a higher prevalence of older brothers among gay men.
- Recent research indicates the FBOE may also apply to lesbian women.
Purpose Of The Study
- To confirm the fraternal birth order effect (FBOE) in gay men and lesbian women.
- To investigate the potential impact of FBOE on anal-erotic role orientation (AERO) in men.
- To explore familial influences on sexual orientation development.
Main Methods
- A preregistered study utilizing logistic regression models.
- Sample included 693 gay men, 843 straight men, 265 lesbian women, and 331 straight women from Czechia and Slovakia.
- Analysis included conventional and nuanced parameterizations of the FBOE.
Main Results
- The FBOE was substantiated in both gay men (OR=1.35 for maternal older brothers) and lesbian women (OR=1.71).
- Non-maternal older brothers did not significantly influence sexual orientation.
- No exclusive link was found between FBOE and receptive AERO in gay men; mothers of gay men had fewer offspring than mothers of straight men.
Conclusions
- The FBOE is a significant familial influence on sexual orientation for both gay men and lesbian women.
- The FBOE's impact on anal-erotic role orientation requires further investigation.
- While FBOE is confirmed, caution is advised when estimating familial influences on sexual orientation.
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