This came up with our group in a Call of Cthulhu game, which I realize is completly different as you are just beggint for wierd stuff to happen to your character when you play. My PC and another PC (played by the DMs wife) had the beginings of a romantic relationship going and after a truly horrible event we took solace in each others arms...affirming life and all that. Since we were pretty upset and didn't say we were taking any precautions the DM rolled for pregnancy w/o telling us (but did inform another player, a female, to ask for certain specifics, like mornign sickness and signs) and critically failed the roll: the PC was pregnant. A short time later in game he had her start rolling for Morning Sickness. That, coupled with some things, meant she palyed with some heavy penalties almost all the time, and she loved every minute of it. We eventually survived the whole thing (although my character needed a bit of therapy and had developed a twitch and a tendency to faint a lot) and had a healthy baby girl post adventure.
OK, so the pregnancy might not be an ideal situation. Metagaming aside, if you don't want your PC to be pregnant then go and buy some lengths of sheeps gut and give them to you partner, again not fool proof but it will drastically improve your chances of stayign that offspring free.
And if you do find yourself with child, go for it. There is nothing to say you can't continue to adventure up to say about 6 months, and then take a short break for about 6 months while you have the baby. Then there are wet nurses and family members who can tend the child while you go adventuring. The child and father are plot hooks waiting to happen.
Beign pregnant wont ruin your character, if you don't let it.