Looking after kids is hard on this game as they get very weak very quickly if u leave them without food. (always check your fridge) do not fast forwards too much cause then they can get weak, very weak, starving, a bit sick, sick etc.
It is common knowlege that you drag your mum or your dad on top of each other. Then they will walk to couch, bed or other comfertable things and try for a baby. Sometimes they will say they cant agree to have one. Rubbish! Just keep dragging till they finally do it. If you have already had a baby recently then they may say it is too soon to have one, if they do get a baby boost $2500 or you wait.