your tamagotchi must be an adult to have a baby. either the matchmaker comes and pairs you up with another tamagotchi to mate and have a baby or you mate with another tamagotchi you connected with. the matchmaker will come when your tama is 5yr old or up at 10:30am, 3:00pm, or 7:00pm. she will not come when your tama turns into an oldie. you also have the option of mating with another tama you connected with. must be of opposite gender and must be 5yr old or up. they also have to be partners, or have four hearts in the friends list. if they have four hearts then they will mate and have babies usually at 5yr old. that is when your tamas will have a baby, it will not have a baby out of the blue. you have to mate and after you mate, it will have a baby, just like that.
sincerely,Tamapal3000