Question

Can a parent with dark brown hair and one with blonde hair have a normal (lightish/auburn) brown hair?

Answer 1

Basically it is more complex then just one locus gene interaction, but basically if both parents have brown hair they can have a child with blonde hair because both parents could be heterozygous for brown and pass on the recessive allele for blonde hair. in simple genetic analysis this would happen to 25% of the children.