A brown-eyed woman married a blue-eyed man. What kind of children will they have, as a percentage?

The gene for brown eyes (let’s call it A) dominates over the gene for blue, which we will designate as a.

We do not know the genotype of the brown-eyed woman. She may have genotypes AA or Aa – in both cases, the eyes will be brown.

The genotype of the blue-eyed man is aa.

If the genotype of the brown-eyed woman is AA, all children will have the Aa genotype and brown eyes.

If the genotype of a brown-eyed woman is Aa, then genotypes are possible in children: Aa and aa. Their ratio will be 1: 1. Thus, half (50%) of the children will have brown eyes, and the other half (50%) will have blue eyes.