It's a Pigeon Pair
My son and DIL are very happy, though when I said to my son I thought there must be at least one boy in "the mix" because he had sounded so pleased, he said he genuinely was that happy because he had "seen my babies hearts beating", if you knew tough guy Matt, you'd know why that brought a lump to my throat.
The babies are a little smaller than the Obstetrician would like... they are at the very bottom of the "normal" range, but there could be a discrepancy of a week in their dates, which could account for it. They will keep it closely monitored (but didn't say what could actually be done about it!)
The good news is that Twin One (now know as the Princess, lol) has caught up a lot, there is now only a couple of percent difference in size between she and The Little Lad.
Anyway, thought I'd share :-) Donna