Vacation rentals and minimum age restrictions?

[Brian Flounders]

Hey everyone, 

Just had a quick question regarding age as a protected class.  I am aware that the Fair Housing Act protects from discrimination for housing. You cannot factor someone's age into your rental decision (presence of young children/seniors). Is age actually a protected class? Or is it a generality and encompassed by the protected classes familial status (having children under 18) or senior class (needing care from family or friend).  

My question is about renting to people between the age of 18 and 21 for a vacation property. Our main concern is underage drinking and being held liable for it. My siblings and I own a place on the New Jersey coast, and we have had inquiries from a group of four girls from Philadelphia (ages 20, 21, 21, and 18). They have a reference from their boss, who randomly happens to be friends with my uncle. So I trust his reference. 

1.) Can we legally advertise that you must be at least 21 to apply for the vacation rental? Or is that a no-no, according to the law? It seems to me that it would be fine.

2.) If we allow rentals between the ages of 18 and 21, are we allowed to stipulate that those who are not 21 must have a parent co-sign the lease?

Thanks so much!

Brian