corgikelly i can sympathise with you massively. We had the same dilema.
OH and i, whislt engaged, aren't married. We have put the wedding off for a year as OH was insistent that he wanted at least one little one at the wedding. I am 17 wks pg by the way.
I was terrified of telling MY parents (we knew his would be tickled pink) as my parents are quite religious, and we thought would like your parents frown on the morals of it, despite the fact we've been together for five years and are planning our wedding. We eventually came to the feeling that we didn't need their approval, and once the bubba arrived they would almost certianly come round to it.
However, we needent have worried. While i think they would have like your parents frowned on the idea of us trying (we didn't tell anyone we were) when they were faced with the fact the deed was already done they were and are great. Nothing negative was said to us at all, i heard via my sister that my mother wishes we had waited until we were married, but fully accpets this is our life.
They knows we are happy, stable, loving couple, who can easily afford to bring up a baby (i know that would be a worry of my dad's if it wasn't the case!) and are now over the moon. They have just returned from holiday with a little hoodie for "Bean"
The only advice i can give is to catch them in a good mood.... i first told them about my degree classification being a first class degree, and then followed with........ And we're having a baby!
Worked a trick, celebrations all round.
sorry, i know i've written alot, but finally, the most important thing for now is YOU and OH are having a baby that YOU want..... Enjoy your pregnancy, whateveer happens with telling your parents, even if they aren't great at first. They'll come around.
Good luck xxxxxx