CitiDad is evolving. Out of his humble, Teva-bound primordial pedaling, New York's shiniest parenting prototype has since exhibited increasingly interesting methods of conveying progeny as parcel—the Forward Facing Pencil, the Faith In God. But now a CitiDad in Soho has stumbled upon The Sling, and nothing will ever be the same.

"His pants fit well, yes, but the first thing you notice is his sweater," says Dr. Goren McGeeney, a professor of Urban Dad psychology at Petitfours University. "Cable-knit, soft—it signals a sort of nurturing power that turns heads."

Dr. McGeeney dismisses concerns that neither CitiDad or his passenger are wearing helmets, citing research showing that helmets might actually make cyclists less safe, and also the fact that this is blatant mate-seeking behavior.

"Suppose they were both wearing helmets," McGeeney says, taking a deep draw of his unfiltered cigarette. "You might attract some of the sensible types, but no one who is willing to skip a Monday night yoga class to share a plate of spiced meats and a rich Carignan blend."

Soho CitiDad's lack of a wedding ring is also an integral part of his sartorial slight of hand. "The hand is bare, you see," Dr. McGeeney says, lighting another cigarette off the end of his first cigarette. "Your eye, faced with flesh, hungers for metal, for glory. Down you look, and there are the buckles! The boots! This CitiDad," Dr. McGeeney says, shaking his head and smiling. "There will be many others."