There is no simple answer to the question, 'Are some people born lesbian or gay?' There are some theories that stress biological differences between heterosexual and homosexual adults, suggesting that people are born with their sexuality already determined.
Are people born gay or choose to be gay?
The American researcher Dean Hamer published research that seemed to prove that homosexual orientation could be genetically transmitted to men on the x chromosome, which they get from their mothers. However when this study was duplicated it did not produce the same results. A follow-up study which Hamer collaborated on also failed to reinforce his earlier results.
Subsequent research published by George Rice and George Ebers of the Universty of Western Ontario has cast doubt on Hamer's theory. Rice and Ebers' research also tested the same region of the x chromosome in a larger sample of gay men, but failed to find the same 'marker' that Hamer's research had found.
Claims that the part of the brain known as the hypothalamus is influential in determining sexual orientation, have yet to be substantiated. It is generally thought that biological explanations of sexuality are insufficient to explain the diversity of human sexuality.
“How can science tell you what I am? I mean I've had boyfriends, and was happy with them, had girlfriends and may have boyfriends again for all I know. If it's a gay gene what's going on? Is it just turning itself on and off in my head? It doesn't feel like biology it feels like love.”Jo
Psycho-social explanations offer a variety of factors that could contribute to the development of a person's homosexuality.
For example, a female dominated upbringing in a gay man's past, with an absence of a male role model. Others stress adherence or deviance from conformity to gender roles, and individual psychological makeup.
While none of these factors alone completely answers the question 'what causes homosexuality?', they rule out some things. For example, lesbian and gay young people are not 'failed' heterosexuals. Also, homosexual partners are generally of the same age proving wrong the assumptions that young people are 'turned gay' by older people.
What is clear is that people's behaviour is influenced by their family environment, their experiences and their sense of themselves. Beliefs about sex are initially shaped by family values. Later on these beliefs may be shaped by pleasant and unpleasant experiences of sex and also shape their choice of activities and partners. Throughout their life a person's sense of who and what they are has a strong impact on their sexual development and experience.