Among your answers I have found one like this:
"A: There are many different customs among many nations concerning marriage. Some societies tolerate or even encourage polygamy and some forbid it. The Noahide law establishes only the minimum required to be a righteous man before God and not the maximum. So the question of having many wives or not is the prerogative of the court of every society. For example, we have a tradition that the court of Shem, the son of Noach, forbid prostitution, even though this is not included in the seven laws."
Does it mean that 7 laws do not prohibit explicitly a prostitution?