I guess I should have said this in the last post. We do not plan on finding out the sex of the baby until he/she is born. Not because we don't want to know (and it's killing Ian not knowing!), but because we're choosing to have as little intervention as possible, including an ultrasound.
So, if we find it medically necessary to have an ultrasound (such as if I hit 42 weeks and need to check the amniotic fluid), we may find out the sex then. Although I think if we can wait that long, we could wait until the baby is born!