Oryan said:
I thought of doing this but the stubborn side of me says, "That would ruin the realism of the world". Realism in a fantasy game? Yeah I know but it's like me warning ahead of time that an item is cursed & asking them if they'd like to put it on. Or like God coming down and asking her if she wants to get pregnant for sleeping with the NPC. I know it's a serious enough angle to warrant an out of game discussion though....what do other people think about asking her before I do it?
Absolutely ask her first.
It's a social contract thing. To take your "cursed item" analogy a bit further: In 1E, it was part of the social contract of the game that any time you used a magic item of uncertain provenance without carefully vetting it first, you were taking your life in your hands, essentially handing the DM a warrant to mess you up in creative ways. So it was okay to occasionally toss a cursed item in with the loot, even one that would alter core elements of your character concept.
In 3.5E, on the other hand, cursed items are no longer an expected thing for most groups. While they do still have a spot in the DMG, I've never seen them used in an actual 3.X game. They've been more or less stricken from the social contract. In a group that doesn't use cursed items, it's not generally acceptable to put in character-altering curses like the
girdle of masculinity/femininity. Players don't expect it, so they don't take the precautions they otherwise would.
Pregnancy is similar. If you'd made it clear to your players that pregnancy was something players had to worry about, and a PC had sex without taking precautions, then it would be acceptable to spring a surprise pregnancy on the character. However, pregnancy is not a part of the social contract of most groups; it's assumed that female PCs arrange for their contraceptive needs "offstage," or else they just get lucky. In that environment, this is the kind of change you really need to get the player's permission for.