Completely unrelated to the topic at hand, the child did not initiate the encounter, and one can safely assume did not enjoy it.
A child who experiments (say with other children) but does not enjoy the act.. As I have already mentioned in a previous post, this is a whole subject in itself. Tasting beer doesn't make you a beer drinker. If they enjoyed it (a very subjective measure, one that you or I cannot answer for them), they have a bisexual disposition.
Most homosexuals probably begin with heterosexual partners (just guessing here, I have no evidence of this), before they work out it's not for them, that doesn't make them bisexual. If they enjoyed heterosexual encounters, and later by chance found out homosexual encounters were also good, and so figured they would remain with the same sex from that point on, this is just not the same thing, it would be more accurate to call them bisexual.
Not everyone falls under a neat label, there is a spectrum. Fortunately I don't use someone's label as a tool to oppress them, so I won't lose sleep if I get it wrong. What we're really debating here is intent versus appearances, and there is scant evidence of someone transitioning from one sexual orientation to the other. There are few studies on this I imagine, and you're welcome to post studies if you have any.
