I love knowing each baby’s sex, but equally like not knowing their zygosity, i.e. whether they’re identical or not. I wouldn’t want the entire surprise of sex discovery at birth, but it is exciting to wait and see if they resemble one another when born. I’m assuming they’re fraternal (non identical), because that’s most likely – 2 out of 3 pairs of twins are.
If they do emerge looking alike, we’ll have to see how they develop to get a clue about zygosity; that will be interesting to watch too, I like to think we have something to discover over time. Identical twins don’t necessarily look alike at birth or even later on however, and contrary to the (mis)information we got from the 12 week sonographer, the presence of two amniotic sacs doesn’t necessarily mean fraternal, ditto two placentas. It’s surprising how many parents of twins are under that assumtion having also been given the wrong information by NHS staff. One placenta can only mean identical twins, though two placentas can fuse, and be delivered looking like one. Monozygotic twins resulting from an early egg split may have a placenta each.
Monozygotic twins resulting from one egg share 100% of their genes, whereas dizygotic share half – different hair colour at birth I guess could be the first clue for us.