What's gynecomastia look like? Does it really look like women's breasts?

It can, but of course that would be an extreme case. More typically, it starts as a little lump under the nipple, usually during puberty. The lump usually goes away with time, but not in all cases. Sometimes it gets bigger, causing the nipple to stick out. In a boy who is a little overweight, the chest might really start to look more like his sister's chest with early breast development. Some kids can even squeeze a little fluid out of the nipple. It's a pretty frightening experience for an adolescent, so lots of guys just ignore it, hoping it will go away--unless their parents push them into seeing their doctor.