Do children loose molars and premolars?

Should a child loose his or her molars and premolars, or are they permanent?

I do believe that any teeth your child has by this age will eventually come out and be replaced by permanent teeth. I am not sure about the "12 year molars", I think those are actually permanent ones that come in about that age but don't replace any that children already have.

So does that mean that when I turn twelve any teeth that I grow after that will be permanent and if I lose them they wont grow back?

Children loose 1st and 2nd priamry molars. They are baby teeth and will be replaced by adult pre-molars. Children get 6 year and 12 year molars and children will not loose these teeth. Children usually get their 6 year molars at 5-7 years old and their 12 year molars at 11-13 years old. Every child is different. Girls usually get their molars early and boys are usually slower. It is a good idea to get sealants put on the molar once they have fully come in. Sealants are a protective coating that goes over the chewing surface of teh tooth. It helps protect agianst cavties, but is not 100%.

my son is twelve and his molar has just fallen out not sure if its meant to come out

Well children do loose their teeth up until 12-13 years of age. Probably it is the second molar falling out which is a primary tooth. Usually these are the last to go as they were the last to come in.

May as well give your dentist a call and have a checkup. If there is a problem he/she will find it. If not you can be sure that a professional can ease your mind in knowing this is normal.