Em and I lived in the Fishtown neighborhood of Philadelphia in 2009. We had just gotten married the year before and moved into a 2-bedroom row home. Like many young couples, we talked about kids. But we weren’t sure. Were we ready? Did we have enough money? Would we be good parents? On our frequent neighborhood walks, we saw young girls pushing babies around in toy strollers. Some looked barely older than teenagers themselves. We whispered to each other: If they can raise kids, maybe we cou...