Ours will be going. Its not so much a cat and baby issue as they have maanged fine with DD#1. But a more people = less space issue.
We have 3 cats, dad-cat (3.5), mum-cat (3.5, no relation to dad-cat), baby-cat (2.5). They are indoor only cats as we are in a flat with no outdoor access. At the point at which we decided to keep baby-cat both me and OH where working and saving to buy a house, flat seemed pretty large and the cats had the run of the house, including thier own bedroom. OH lost his job and a couple of months later we realised it could be a long time before he got a new on and it made sense to have children now with low income and low outgoings. We got pregnan straight away.
As the family gets bigger the space available for the cats gets smaller. LO is now in "thier bedroom", doors have to be closed to keep the cats out of certain rooms at certain times of the day. In the evening we have to close the living room door so we don't wake up LO. We have had to move thier bowls so LO can't eat catfood. The litter tray is very interesting to an 18month old and she is constantly being told to come away (it has a roof on it, so not that bad). The cats like to spend a lot of time in the bathrom, but now even that has to be closed off as LO will go and try and play in it.
So baby stage was fine with cats, but toddler stage with limited room is not working out for us. And since I can't exactly re-home the babies, and we won't be able to afford to buy our own home for a long long time its got to be the cats that go.