The incentive is the net present value of having sex Right Now, versus the cost of money, being unable to sleep for the next 18 years, and financial obligations

The incentive is the net present value of having sex Right Now, versus the cost of money, being unable to sleep for the next 18 years, and financial obligations. Given how often people (in general) don't use a condom, even when they're available, I get the impression that most guys are not thinking very hard about the future.