I think sex is a need, but only if pertains to people touching one another in a loving way. Well, you might say, hugs would be suitable to fill that void then, and I would say, the kind of human touch and level of it is only appropriate with certain people. You can hug an aunt or an uncle, but you're only going to the "ultimate" level with a spouse or significant other, typically. Yes, I know there's the whole casual sex thing, but that's not a need, that is more of a want.