Question

Male-limited precocious puberty results from a rare, sex-limited autosomal allele (P) that is dominant over the allele for normal puberty (p) and is expressed only in males. Bill underwent precocious puberty, but his brother Jack and his sister Beth underwent puberty at the usual time, between the ages of 10 and 14. Although Bill's mother and father underwent normal puberty, two of his maternal uncles (his mother's brothers) underwent precocious puberty.

Answer 1

Male-limited precocious puberty - sex limited autosomal dominant expressed by allele P, which is dominant over 'normal puberty' caused by allele, 'p' that is expressed only in males.
Bill - underwent precocious puberty - PP or Pp
His brother Jack and sister have gone through normal puberty -pp
Mother and father - normal puberty
Two Maternal uncles - precocious puberty -PP or Pp
As maternal uncles have got precocious puberty with the above genotype
Mother will have pp genotype and father will have Pp genotype.

Hence, third option is the correct answer.