Most of the gender related nasty genes are found on the X chromosomes and are recessive. Because women have two X chromosomes, they will need to have the defective recessive gene on both X chromosomes for disease to be apparent. On the other hand, males have only one X chromosome. So if there is a nasty recessive gene on a male's X chromosome, he doesn't have another normal X chromosome to offset the defective gene, and therefore disease will be apparent.. . I don't know the answer to the second part of your question.