Question

A woman gives birth to a set of fraternal twins: a girl and a boy. she also passes on a color-blindness gene. which of the children is more likely to be color-blind?

Answer 1

The boy is more likely to be color-blind from birth.

Answer 2

The boy

Step-by-step explanation:

Color blindness is a X-linked trait. The alleles representing the gene for color blindness are usually located on the X-chromosome of the human's sex chromosome.

The female sex chromosome is XX, hence, the two chromosomes have to carry the alleles for color blindness for the girl to be color-blind. Otherwise, she's going to be a carrier for the abnormality.

The male's sex chromosome is XY, only one allele is needed for the male to become affected by color blindness.

A male child always inherit his X chromosome from the mother while one of the female's X chromosome is always from the father and the other one from the mother.

Hence, the male child is more likely to be color-blind out of the twin.