And back in the early 1900s, when larger families were more common, enough people were concerned about this that there was apparently a problem of people abandoning their 7th sons. So the president of Argentina passed a law declaring himself the godfather of all 7th sons born in Argentina. They each receive a gold medal and educational scholarships until their 21st birthdays, which is a pretty good deal.
The law worked, and parents stopped abandoning their 7th sons. Even today, Argentine presidents still attend at least some of their werewolf godchildrens' baptisms.