16 Weeks and Counting

I am entering into my second trimester and other than feeling a little heavy, things are going great. The baby is approximately 3" long and weighs about 4 oz. It is already breathing amniotic fluid and has a full range of facial expressions. We will be able to tell the sex in about 4 weeks or so. And yes, when we know, you will know. Should we bet on this? What do you think we are having?