Depends on age they become homosexual?
Discussion
Well, I have seen relatively strong evidence for prenatal period being the decisive factor. Far from proven, but strong nonetheless.
If that is the case, we don't become (whatever)sexuals, we just eventually find out. A 5 year old likely has no idea what sex is and what are his/her sexual preferences, because that's just out of scope and possibly beyond comprehension capabilities of the child.
What’s the evidence?
This one's long, but worth the read IMHO.