I'm all for traveling with kids and don't think you should leave them behind or have to stop traveling when you become a parent. That said, I think I would have to advise your friends to wait a little longer on a cruise. It's a lot of money to commit far in advance when your baby isn't even here. I have several reasons, and medical care actually isn't one of them. My DD came 2 weeks late. If this happens to your friends, they'll be awfully close to the age limit for taking a baby. Another thing is that you never know what the temperment of a baby is going to be. Will they be sleeping through the night at that age? Will they handle change well? We started traveling with DD when she was 2 1/2months and she did wonderfully. DS was another story. If we had cruised with him at 4 mo, we would have been exhausted and not been able to enjoy ourselves much. He doesn't nap well in strollers, and likes a little bit more familiarity/routine to his life. He wasn't sleeping through the night until we diagnosed his food allergies at 8 mo and I adjusted my diet. Another thing is to consider how comfortable your friends are with a baby. Is this their first? If it is, have they been around babies enough to be completely comfortable with being parents? DH and I had no problems traveling with our first b/c we have been around babies our whole lives. Our new parent paranoia was small compared to others.
My advice would be to try to cruise a month later (or more). Your friends may get lucky and get a really portable baby who will sleep anywhere, or they may get
