Not necessarily. Environment can warp a person. So can experiences. Most homosexuals admit to having been molested and/or having a domineering Mother.
I have seen no credible, double blind, peer reviewed study to show that homosexuals arise from their environment. I know that this sin is as old as the mankind. This matches my belief that their sin is inborn, at most the environment determines if they act out on their sin (being a homosexual at heart and not in practice is still a sin in my book).