We were told after our last ultrasound that they're mono-di twins! I think we'll do a DNA test when they're born though(curious) to find out if they're really identical. My OB said that's the only way to know for sure, unless they share a sac. We find the whole thing to be fascinating and are really excited to be having twins! We don't care about gender, but already having 2 boys, girls would be neat!