Middle-aged son inherits travel agency. His father had the good sense to send him on a nude cruise before father died, as son was the sort that would never have gone. Another thing father did was to interview some potential sales talent of the attractive female variety, with a requirement in the will that son goes with these women on another nude cruise, so that they know what they are selling.
This could be a series of stories, as he's tasked with going out on excursions from the cruise with these wonderful women. It turns out, father has had a talk with each of these ladies, telling them how there is cash left from his will in a trust to the women from their group that can make a baby with her son. (Not a competition, though, as each woman that gets a baby gets an inheritance, too!) Son doesn't know about this part of the will...