Yes, a child's relationship with his or her parents can cause homosexuality, because if a child has a poor relationship with his or her parents, the child can decide that traditional life is not for them. While homosexuality is part biology, a person who is damaged in their childhood will be more likely to explore an alternative lifestyle.
I have seen many cases of parents who neglected their children
or were too strict. Both extremes can
cause a child to eventually rebel against the parents. Children lash out against their parents in
many different ways. Sometimes this
rebellion manifests itself as experimentation with drugs and alcohol. Sometimes it manifests as homosexuality.
I'd like to first start off by informing those who are hidebound that homosexuality IS NOT A CHOICE. There are so many who are cruel to gays, why would they "choose" to be something so despised? And I know none of you can truly answer that question, because I've just shown you a piece of psychological evidence that conveys quite succinctly that gays don't have that option of sexual orientation. None of us do. If that were so, then technically we'd all be bisexual. I don't know about you, but I didn't choose to have attractions towards the opposite sex, its a naturally occurring interest of mine. Same thing goes with homosexuals.
If this were true, why is it that studies such as 'Bailey and Pillard (1991): occurrence of homosexuality among brothers' and their later study on the 'occurrence of homosexuality among sisters' show that evidence against this? Additionally, if homosexuality had environmental causes, why do children brought up be the same parents identify themselves as having different sexualities?