Question

Consider the genetic cross for sex in humans. XX is female and XY is male. A family has 4 children, all girls. What are the chances that the family will have a boy as their fifth child?

Answer 1

50% (2/4) make the combos with xy and xx

Answer 2

Answer: The correct answer is 50%.

In humans, the females have XX genotype and males have XY genotype. Females produce only one type of gametes ( haploid sex cells) that is X whereas males produce two types of gametes ( X and Y). The chances of having girl child or boy child is always 50% as any of the gamete from male parent can fuse with female gamete.

Refer punnett square.