Is this the first time opening and playing with your Tamagotchi? If so, if you did not set the time, it won't hatch. You have to hit the middle button when the egg is on the screen and set the time and date. Then, it will ask you for your birthday. After you enter your birthday, you will be taken back to the egg screen. Wait about 1 minute, and the egg will hatch and you will find either a little boy or girl to take care of and name.