“My son is 20 and his girlfriend is 16 and having a baby. She got in trouble for truancy and lives with me, while my son lives with his grandma. They went to Maryland and got married, can they get in trouble?”
There simply isn’t enough information in this question to answer it with any certainty. Your question seems to be ‘can an adult get in trouble for marrying a minor whom he got pregnant’, and it depends on so much. Is the marriage legal, or is it void or voidable? That will depend on many factors, including the state in which they got married, the state in which they reside, and whether the minor had the permission of a parent or legal guardian. Moreover, it’s not clear who would get them in trouble, although (and again, depending on the states involved) your son may be guilty of statutory rape (which is illegal even if the minor consents). However, so long as nobody complains, they are unlikely to get in trouble, however they may or may not actually be legally married, and its worth checking with an attorney in the state of residence to determine whether they are, in fact, married.