A man and woman who do not show any symptoms of an inherited disease have 10 offspring - 6 boys and 4 girls. Three of the boys suffer from the disease, while none of the girls are affected. The disorder is most likely to be

The disorder may be sex-linked recessive trait. Either of the parents are not affected but offspring are, so it is a recessive trait. None of the girls are suffering, but half of the boys are affected, so it is most likely to be X-linked recessive (the woman is carrier).