I see two options regarding pregnancy.
1. The developer wrote this story as such, and then it must be accepted as such.
2. If you do change it, perhaps the best option would be to put the main emphasis on the development of the "Master". Because it is said several times in the game that they want to make him the best master of all time. If this is successful, perhaps the rules and the contract can be changed. He would have the power and authority to do so. Because in this case, if a son were to be born, he could be taught from an early age to take over the role of his father later on.
But the final decision is the developer's, and I think it's a shame to get into big arguments because of a pregnancy.