If parents wish to know the sex of their unborn baby, they usually have to wait until weeks 18–22 of development before a sonogram determining the sex can be performed. Based upon your knowledge of...

If parents wish to know the sex of their unborn baby, they
usually have to wait until weeks 18–22 of development before a
sonogram determining the sex can be performed. Based upon
your knowledge of reproductive system development, explain
why the sex of the unborn baby can’t be determined easily
before this time.