If parent doesn't want to know gender of child will doctor reveal that information to grandparents.

Hopefully not: Unless there is a genetic or other defect that only affects one sex, there is no need to know the sex of a baby fetus. It can be exciting and suspenseful, not knowing the baby's sex until the birth. Remember that prenatal ultrasounds were only started in the 1960's. For thousands of years, a baby's sex has been a wonderful surprise at birth!

I doubt it: You could interpret such a disclosure as a violation of the federal healthcare information privacy protection act (HIPPA). Such information is the property of the involved patient or patients and they determine if it can be disclosed to a third party. Unauthorized release can subject the person causing the violation to fines up to 100k per disclosure.