You need to pass the propose marriage goal and get engaged and then after a while comes the get married. After that you buy a crib and tap on it the sim in progress icon comes up with a time when it will be complete after that time tap on it and you have the baby. Babies dont do much but take a lot of looking after......much like real ones. So people say they are bored with them really quickly. So they get a toddler and then they whine they cant do anything for themselves.....ummm just like real ones except that they are very demanding an d take a lot of time to be looked after and so people get bored with them and then we have the current situation where they want them to grow up. Which is right back where we started with grown up sims. Me i'd stop right there.