I think it is legal because age discrimination only applies to older people and not to the young. My grandmother lives in an apartment complex for 55+, no kids allowed.
But it seems like that kind of housing discrimination is covered under federal law (Title VIII, Civil Rights Act 1968), as least as I'm reading it.
__________________ Delta Sigma Theta"But if she wears the Delta symbol, then her first love is D-S-T ..." Omega Phi Alpha"Blue like the colors of night and day, gold like the sun's bright shining ray ..."
Also keep in mind these are prolly privately owned communities. Private vs public companies have different rules. That's why private colleges can be all male or all female vs public colleges which have to accept both genders.
Based on the law class I took last year if no public money is taken schools and companies have greater leway in what is legal.