Procreation is, of course, sexy. Combining the very stuff of one's body with another: hot. If you listen to the evolutionary biologists, much of romance is about finding, testing and winning the right mate (though I think them cynical and unwise -- there's a lot more to love than making the babies, and a lot more to human consciousnesses and cultures than merely hormonal rushes).
Still, the baby-love connection is strong, and this Valentine's Day card gets straight to the point: it combines representations of sequences of your DNA with those your loved one, and makes them into a handsome piece of art.
Cheap biotech ain't all about fighting cancer and smartbreeding superorganix. The street may find its own uses for things, but so will Hallmark.