You don't even have to wait till she shows up with a baby. Just watch the population number go up and then you know you have a baby. When they have a baby I just reward them and let them go to the hut. Sometimes if I don't want them to take an hour to get to the hut I will breed them just outside the hut so their reward doesn't take long. Have you ever noticed that when the guy comes out of the hut he has a smile on his face looking around to see if anyone noticed! Also if you breed them infront of everyone everyone will turn their head and watch even the children.