WHEREAS some doubts have arrisen whether children got by any Englishman upon a negro woman should be slave or free, Be it therefore enacted and declared by this present grand assembly, that all children born in this country shall be held bond or free only according to the condition of the mother, And that if any christian shall committ fornication with a negro man or woman, he or she so offending shall pay double the fines imposed by the former act. - 1662 VA law

It was the same law, partus sequitur ventrem or "birth follows the womb" that governed the status of children. Born to a free woman, you're free. Born to an enslaved woman, you're enslaved. It's noteworthy to highlight the opening of the statute above, "WHEREAS some doubts have arrisen whether children got by any Englishman upon a negro woman should be slave or free..." which indicates what their concern was. Previously under English common law status follows father as we established a patriarchal society, but the amount of enslaved men with free women vs free men with enslaved women gave them reason to flip the legal doctrine respecting status at birth. This is why they had to codify it - it was the opposite of the historic precedent which is common law. In other words, what you're talking about was very rare. In many cases the closest you'll find is an enslaved man and an indentured woman having a child, and in that event the child was usually held in apprenticeship and additional time was added to the woman's term (and probably recieved a whipping) regardless of the fathers condition as it violated her contract, however they remained free (as opposed to enslaved) even in that situation, which would depend on when/where as to exactly what happened.