Does it mean the color of our skin? No that can't be it. As I've been taught, love is supposed to be colorblind. What would one specific color have to trump another? I've had friends say "so and so race are better lovers". How would they know that one is better than another unless they have BEEN with every race? I don't intend to state or even assume that these friends are promiscuous because I know they're not but it doesn't paint a really great picture. As far as I know, whatever color our skin is, one thing remains true: we all bleed the same color, red.
Does it mean age? OK I can sort of understand this from a lawful standpoint. Most states deem the legal age of consent as 18. Even so, love is supposed to be ageless. We as humans are like fine wine, we only improve with age. Granted, some of our parts are no longer functioning as we age without use of certain medications but love isn't all about sex. Its about the connection between two people, that is what love is. You're only as old as you feel.
Is it social status and the possessions you have? If that is the case, that is petty and selfish. Money is transient. Its always transferring from one hand to another. I would rather have the permanent thing that love entails than something as inconstant as paper currency.
What else is there? We bleed the same blood. We cry the same tears. We breathe the same air. We share the same sky. We are no different than anyone else. There are no types...just simple gripes.