Question: I know genes are past on from parent to child, but how many exact similarites are passed on?

Lena Ciric answered on 12 Mar 2012:

Hi Tobes. The short answer to your question is half from each parent.

But the way in which these then come out as traits in the child is important. We all have two sets of 23 chromosomes. All our cells therefore have 46 chromosomes, except for the sperm and egg cells which have 23. When a baby is conceived it gets one set of 23 from the mother and one set from the father. The set it gets from each is a random selection from the two sets each parent has. So, the child has two genes – one from each parent – for each trait (e.g. height, eye colour…). Sometimes, one of these genes is dominant and one is recessive. The dominant of these two genes then dictates this trait in the child. But a lot of the time genetics are much more complicated. So it’s the genes themselves that determine exactly how much you are like each of your parents.