I don't know which is more reassuring: the fact that this study about the possible obesity prevention benefits of hormone-filled baby formula was published in a journal called Chemical and Industry, or the quote from the lead researcher who argues that adding enough appetite supressants to a newborn's food supply to permanently alter their body chemistry is, "still a grey area. One could argue that as you're replacing something that should be there, it's not pharmaceutical."
Either way, though there are now apparently cages full of sexy-skinny mice in labs across England, the fat-preventing formula probably wouldn't hit the market for ten years. Just when your kid starts getting really self-conscious about being fat. Sorry!
update: After reading MattDM's good comment below, I took a closer look at this study and the press release accompanying it, "Lean for Life: Baby Formula that Fights Fat," [see a slightly adapted version at Science Daily.] which doesn't mention breast milk at all. But nor do they mention any of the extensive research already done in leptin augmentation or replacement for, say, premature infants who lose access the leptin they get through the placenta.
A more useful context would have been the one Matt mentions, of seeking to engineer formula that's closer to breast milk's own composition, but that's one the researchers and the chem industry journal didn't choose, probably because it might have meant less media attention. Or negative contrasts to the shortcomings of formula in the first place.
But I think it's beyond that, since the study and especially the press release emphasize skinny-for-life, which is not a result seen in studies of breastfed, leptin-filled kids. What I think they're really gunning for, if not directly talking about, is designing a superformula that outperforms [sic] breast milk. Their argument that this particular hormone additive is present in breast milk isn't about the formula's benefits; it's an attempt to lower the regulatory hurdles they'd face.