I've thought the same thing, using the same methodology (that is, using the Drake Equation as a basis and coming to the conclusion that there are far too few members of the fairer sex that are of acceptable age/health/mental capacity/etc that would be willing to reciprocate interest), such that the likelihood of meeting any one of them before they're already paired with someone else (and/or before I become too bitter and heartbroken to care) is actually perishingly small... :-(