If both parents have blonde hair, is it possible for their child to have brown hair?

Question

If I understand correctly, in order to be blonde, a person must have two recessive blonde genes. If that person had a child with another person who was also blonde, how is it possible for them to have a child with brown hair when there was no dominant gene passed down? Is it impossible? Will light-haired parents always have light-haired children?

Answer 1

YES

Chemistry
There are 3 hair pigment chemicals, which are black eumelanin, brown eumelanin, and pheomelanin. As can be inferred, black eumelanin is black and brown eumelanin is brown. Pheomelanin is red. A small amount of black eumelanin in the absence of other pigments causes grey color. A small amount of brown eumelanin in the absence of other pigments causes yellow (blond) color.


Genetics
At least two gene pairs control human hair color. One gene, which is a brown/blonde pair, has a dominant brown allele and a recessive blonde allele. If a person carries the brown allele, he will have brown hair; otherwise, he will be blonde. This also explains why two brown-haired parents can produce a blonde-haired child. The other gene pair is a not-red/red pair, where the "not-red" allele (which suppresses production of phaeomelanin) is dominant and the allele for red hair is recessive. Since the two gene pairs both govern hair color, a person with two copies of the red-haired allele will have red hair, but it will be either auburn or bright reddish orange depending upon whether the first gene pair gives a brown or blonde hair color respectively. The recessive genes for both brown/blonde and red hair are found nearly exclusively in populations of Whites and Caucasians.There is also a black gene, usually related to darker skinned humans.

However, the two-gene model cannot explain the various shades of brown, blonde, or red which may occur (for example, platinum blonde versus dark blonde/light brown), or why one blonde child's hair might turn brown as he grows up while another blonde child's hair does not.

According to some research, there are several gene pairs that control the light versus dark hair color in an accumulative effect. Therefore, the more of these that are dominant, the darker the hair will be.

http://en.wikipedia.org/wiki/Hair_color

The color of a person's hair is determined by the amount and distribution of melanin in the cortex of each hair (the same melanin that's found in the epidermis). Hair also contains a yellow-red pigment; people who have blonde or red hair have only a small amount of melanin in their hair. Hair becomes gray when people age because pigment no longer forms.

http://www.kidshealth.org/parent/general/body_basics/skin_hair_nails.html

Read more about this at these two sites good information.

Answer 2

yes if one of their parents or other ancestors had brown or any other color that gene can dominate the blond gene creating offspring with darker hair

Answer 3

Yes, it is possible. The parents still have the genes of their families, and it is possible that many generations ago, somebody in their family had that hair color :-)

Answer 4

it is possible. Hair color is not determined by one gene exclusively. It is however unlikely

Answer 5

nope, cause bb x bb is always bb.
but i'm pretty sure hair, eye, and skin color involves more than just one gene.

Answer 6

only if the mailman has brown hair

Answer 7

yes it is possible

Answer 8

the babys hair could be any color.

Answer 9

most probably
but
odds always there

Answer 10

of course it is. that's what genetics is all about.