Eh, their hearts are in the right place, unfortunately I'm a tad shocked that no one had the common sense to nix these in the planning phase.
Sexual anything is a private matter. Not dirty, and it's not necessarily bad. Just private. It's the same reason I would go talk to a doctor if I had some sort of embarrassing medical problem rather than taking to the streets in an "I Have Hemorrhoids" tee-shirt. It's not something that you just discuss with anyone.
I'm just afraid that the people they're hoping to reach are going to see these shirts and add them as more fuel to the "Christians and the Bible are Anti-Sex" stereotype. (We're not, by the way. God made sex, and wholeheartedly endorses it.)