so, I'm 16 weeks along & so much bigger than the majority of my other pregnant friends. my sister keeps saying its bc I was chunky before then, but twins run in both my fiances family & mine & i just have this feeling there may be two in there.. I had my first ultrasound at 6 weeks & they were able to find the heartbeat easily. there was only one heartbeat & one sac. is it possible that they missed one? i should also add that i did get the genetic blood test & there was only one result but I've read that they may only be able to detect one gender at a time..