Question

Haemophilia and red green colourblindness is usually observed in men. Why?

Answer 1

1. Red-green color blindness and hemophilia are X-linked recessive conditions.  Due to the fact that boys only have one X chromosome (XY), if they receive a defective gene from their mother, they will manifest the condition since the Y chromosome lacks a homologous allele.
2. Because females have two X chromosomes (XX), the disorder is less prevalent in females; that is, females can be carriers (heterozygous condition), normal, or exhibit the disease (homozygous recessive).