As long as she fills both my physical and mental standards, then i'd totally do it.
Must be loyal, loving, willing to have sex and is normal enough mentally to where she can consent, plus not be super mentally ill and crazy. Down syndrome is bad to have, but if anything it'd make her be more tolerable as a person. As for physical attractiveness, if she was a virgin, and i found her attractive (which tbh is not hard at all considering that i find attractive) then i'd do it. Also for cucktears reading this, i don't mean "It'd make her more tolerable" as in "I want it to be easier to control her and be possessive". What i mean by that is agree with me on things, and don't be a hypergamous slut. Simple.