Here are three articles from three different sources on the question of whether a person is born with same sex attraction. A few other links follow these three excerpts.
‘I Was Born This Way’
By Clayton E. Cramer
One of the more effective arguments used by those arguing for same-sex marriage and sexual orientation anti-discrimination laws is that homosexuals have no choice in the matter — that sexual orientation is something that you are born with, and you can’t change it. The claim is that this is a natural part of human variability, no different from skin color or hair color or how tall you are. As an acquaintance — a generally conservative, gay high power rifle shooter (talk about being a member of the world’s smallest cross-section of identity groups) told me once, “Why would anyone choose to be gay?”
There is pretty persuasive evidence that what determines sexual orientation, at least for some homosexuals, is environmental. At a minimum, the evidence of a connection between being sexually abused as a child and homosexual or bisexual orientation as an adult is so widespread that the refusal of the scientific community to seriously consider a causal connection suggests a willful blindness.
No one is born homosexual and here is why
By Alessandara
I believe one of the main problems refers to the false opposition between inborn versus “free” choice. The problem with this false opposition is that it eliminates from consideration a very large and significant part of the mind that is neither inborn, nor chosen. There is a very important third sphere that is being left out and which is very real and which complements the other two.
A person is born with a developmental matrix, including to develop into a heterosexual adult that has healthy, adult relationships with the opposite sex. However, this matrix is not finished and it will change (including being deformed) in a variety of directions. Therefore, the mind has a deep plasticity; regarding many characteristics, it’s not hard-wired. Although you began to feel certain feelings about boys early on, if you had been abused or had had other deforming experiences, they could impact how your mind functioned regarding sexuality and the opposite sex.
So, a key point is that any person’s mind will develop conscious and unconscious mechanisms and dynamics that can deeply affect it later in life, which were not present when this individual was born.
[…]
If you are stupid enough to believe that people are born homosexuals, you are stupid enough to believe that people are biologically determined to be couch-potatoes! The science is the same.
Same-Sex Science: The social sciences cannot settle the moral status of homosexuality
By Stanton L. Jones
Many religious and social conservatives believe that homosexuality is a mental illness caused exclusively by psychological or spiritual factors and that all homosexual persons could change their orientation if they simply tried hard enough. This view is widely pilloried (and rightly so) as both wrong on the facts and harmful in effect. But few who attack it are willing to acknowledge that today a wholly different, far more influential, and no less harmful set of falsehoods—each attributed to the findings of “science”—dominates the research literature and political discourse.
We are told that homosexual persons are just as psychologically healthy as heterosexuals, that sexual orientation is biologically determined at birth, that sexual orientation cannot be changed and that the attempt to change it is necessarily harmful, that homosexual relationships are equivalent to heterosexual ones in all important characteristics, and that personal identity is properly and legitimately constituted around sexual orientation. These claims are as misguided as the ridiculed beliefs of some social conservatives, as they spring from distorted or incomplete representations of the best findings from the science of same-sex attraction.
Other relevant articles:
Book: What Nature Intended — Six Factors Demonstrating Homosexuality to be a Dysfunction
Pro-homosexual agenda arguments are “fact-less, emotional, and based on false premises”
The “homosexual rights” agenda is based on bad science