Develop it into a white label site at first obviously in the pediatrician niche/sector and then you can find some potential buyers (again, obviously pediatrician(s) or people/companies interested in pediatrics)...
Nice pick up, I'd get the plural form as well.
Yes you're right it's too early to tell how .online will do now, but the early bird catches the worm.
high $xx to reseller, mid to high $xxx to end-user atleast