Here's a reference you might find informative from What Causes Homosexual Desire and Can It Be Changed?
4) Early homosexual experiences influence adult patterns of behavior
In the 1980s, scholars (12) examined the early Kinsey data to determine whether or not childhood sexual experiences predicted adult behavior. The results were significant: Homosexual experience in the early year, particularly if it was one's first sexual experience - was a strong predictor of adult homosexual behavior, both for males and females. A similar pattern appeared in the 1970 Kinsey Institute (4) study: there was a strong relationship between those whose first experience was homosexual and those who practiced homosexuality in later life. In the FRI study (5) two-thirds of the boys whose first experience was homosexual engaged in homosexual behavior as adults; 95% of those whose first experience was heterosexual were likewise heterosexual in their adult behavior. A similarly progressive pattern of sexual behavior was reported for females.
Really all you need is a kid who has no strong male role model, no positive masculine affirmation. He'll already be uncomfortable in or unsure of his own masculinity. If there's a domineering, emasculating Mother ("Mother's gonna keep you right here under her wing. She won't let you fly, but she might let you sing"), there's an even greater chance the kid grows up queer. Any sexual abuse, particularly same sex, can seal the deal.
The guy will learn to eroticize masculine traits in other men, when what he really needs is to feel those traits in himself. It's sexual cannibalism: they are "eating" masculinity from other men.