Why would a kid whose parents didn't lie, wasn't exposed to others who lied, wasn't lied to as a child, becomea liar?
Some people have certain temptations, some have other temptations. For some people, it's easy not to lie, but hard not to fantasize about sex all the time. Some people can't speak without lying.
Some people used to lie, decided it was wrong, and stopped. Some people had a hard time with sexual promiscuity, decided it was wrong or dangerous, and stopped.
Similarly, some people - for various reasons - have difficulty with SSAD - Same Sex Attraction Disorder. Some people consciously choose to engage in same sex acts, some choose to engage in bisexual acts. Others just find themselves drawn to such sexual behavior, for many reasons.
I know a woman friend years ago (early 80s) who confided in me that at one time in her life she had engaged in "three ways" with a man and another woman. I was shocked (not ever having hung around with people who did that kind of thing). This woman was at that time (and still is, AFAIK) happily married to a man. When I asked her how could she do such a thing, she said: "An orgasm is an orgasm, however you get it."
A lot of activities are shocking or hard to do the first or second time, but if a person keeps indulging or engaging in them, they become habituated - especially if there is some kind of gratification or pleasure.
For instance, smoking. I started smoking when I was 12 or 13. It was horrible, it made me sick, nauseated, headachey, but gosh! I persevered. Within a few months I was smoking unfiltered Camels with the best of them.
But now? You couldn't pay me enough money to smoke a cigarrette. I decided it was wrong for me, unhealthy, and so on, and I quit.
Because he's afraid of punishment, he did something he shouldn't do, doesn't want his parents to be mad at him or think less of him, to protect a friend...these are all reasons that come to mind.
Does this apply to someone becoming homosexual..
does he become gay to avoid punishment..
does he become gay because he did something he shouldn't do..
does he become gay to make his parents think more of him..
or does he become gay to protect his friends.
I think we're talking two different things other than the propensity to lie may also be a trait.