Blue eye is a recessive characteristic. The genetics for eye colour are really simple. You have two genes for eye colour, both need to be blue for you to have blue eyes. For brown eyes you can have either two brown genes or one blue and one brown. The physical colour of the eyes is the same in both cases.

Both my husband and I have blue eyes, so it is not possible under any circumstances for our children to have brown eyes.

My brother has brown eyes, as does his wife, and both their children have blue eyes. This is because both their granny's had blue eyes and my brother and his wife both have one gene blue and one gene brown. There is a 25% chance that any of their children have blue eyes, and as it happens they both do.

With regards to Michael, I don't think that those children are biologically his, either. But he is still their father.