A parent tells the nurse, "I am worried about my 13-year-old son. He hasn't started puberty, and my daughter did when she was 11 years of age. "Which would the nurse explain to the parent about puberty in boys and girls?

Unusual because the onset of pubescence is usually the same in siblings

Unusual and requires further evaluation of the son

Abnormal because the onset of pubescence is usually earlier in boys than it is in girls

Normal because the onset of pubescence is usually earlier in girls than it is in boys