A Man and Woman Are Eager to Determine the Sex

Multiple Choice

A man and woman are eager to determine the sex of their unborn child and have asked the nurse at the fertility clinic how this is possible at an early stage of in vitro development. Which of the nurse's responses best captures the genetic rationale for early sex identification through tissue samples?

A) "The inactive X chromosome can be visible in a female."
B) "The cells of a male contain a Barr body that can be visualized."
C) "A normal female lacks Barr bodies."
D) "The number of visible Y chromosomes indicates the sex."