External link. The nature—nurture debate still rages in the minds of many scientists and scholars, despite the consensus that these are complementary rather than mutually exclusive explanations. Each participant was also asked "What percent of your sexual fantasies during masturbation involve women? Whether and how long participants were reared with these siblings was also examined. This particular effect is also relatively small in size, so there will be many exceptions.
The fraternal birth order effect has been confirmed to interact with handedness  as the incidence of homosexuality correlated with an increase in older brothers is seen only in right-handed males.
Lagercrantz D. Hines M, et al. Open in a separate window. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission.
Quantitative assessment and correlation with pregnancy history.