I don’t believe that being gay has anything at all to do with education or experiences. Children/People won’t become homosexual because they know that homosexuality exists. Forgive me, but it sounds like you fear that gays might influence our children to choose the “wrong” sexual preference.
However sexual preference is nothing you can choose from, either you’re straight or homosexual. A straight person can’t be forced to become gay/lesbian and the other way 'round.
Here are two wikipedia-links on the topic:
On the other side, I think homosexuality shouldn’t be included in the game, unless in some plot-relevant way. A regular homosexual person in that time just wouldn’t show his/her feelings, for reasons mentioned above. There could be a quest about a gay couple in trouble and the player decides to help them or not.
I’m not saying it can’t be included, but it’s the devs decision, as it would require more work and time to code the consequences (being hunted down and thrown in a dungeon), for a (probably) minority of the players.