Zoology - Principles of Inheritance and Variation Question with Solution | TestHub

In human, male sex chromosome is hemizygous, $\mathrm{XY}$ while female are homozygous $\mathrm{XX}$. Thus, any recessive gene present on $\mathrm{X}$ chromosome will get expressed in male. In female, those genes can only be expressed if present in homozygous recessive condition on both X-chromosomes.