Too Many Sisters Affect Male Sexuality

David Crews, a psychobiologist at the University of Texas at Austin, has been studying how the lives of early rats affect their adult life. Interestingly he has found that the ratio of male to female siblings in a family unit can play a significant role in the male's masculinity and attractiveness to other females.
Some researchers have found that female fetuses sandwiched between two males tend to grow up with more masculine qualities because of the contact with the male hormones in the womb. But the ratio of male to female fetuses in utero itself had no affect on adult personality.
Crews focuses more on after birth influences in his study. Males growing up with more male siblings, more female siblings, and equal numbers of male and female siblings were all studied. Results showed that while all the male rats were sexually active, males that grew up in families with more males, or equal numbers of males and females spent more time mating and were more attractive to females.
Though this study only proves that this phenomenom is true in rats, the results can be correlated to human development. It shows that family life, the male to female ratios of the family, and interactions with family members play a major role in personality development.
Sexual orientation is a hot topic of depate today. Whether its hereditary or caused by environmental factors. I think this is an interesting debate and I chose this arcticle because I think there could be some overlap between the two. Its amazing to me how much your family shapes your personality, social life, and even sexuality.

http://www.medicalnewstoday.com/articles/205485.php