Yes, I imagine this would only be useful in long-term relationships. But then, isn't that where most fucking happens? (For everything else, there's condoms.) Actually, this is one reason I like the idea of the 6-15 year reversible variety, it's just about perfect for men. Too bad you U.S. guys are likely to get the hormonal type--welcome to the guinea pig cage.
With males using daily contraceptives, we'd definitely need abortion as a backup. Or perhaps it would be enough for men to have the certain knowledge that they would do half the childcare.
Jenny Brown