Genotype   Phenotype
female male
BB Bald     Bald
Bb Not bald     Bald
bb Not bald     Not bald
Sex-influenced Pattern Baldness

Pattern baldness (hair is thin or absent on top of the head) is more prevalent in males, since the heterozygous genotype exhibits this phenotype only in males.

Females who do inherit the BB genotype exhibit a much less pronounced phenotype and express it later in life.