Re: if i dye my sims hair with the salon will it go onto her children?

@katelynk005  I've moved your thread to the Sims 3 section.

The genetics of a child are determined at birth, with some twists.  It's decided at some point before, maybe even conception, which features are inherited from which parent, but those features aren't assigned until the child is born.  So if you dyed the hair of one of the parents during the pregnancy, that color could be transmitted to the child later.  (I've had this happen a couple of times, although luckily it could be undone with a convenient mod and a couple of clicks.)

However, there's no reason that a dye job after birth should change the child's hair color.  And without mods, the grandparents' genetics won't affect the grandchildren, so there's no reason the dye would affect subsequent generations.  Still, keep in mind that there's a 10% chance of a mutation in the unmodded game, so you might see a different hair (or eye) color no matter what you do.