They both want a baby. If only they could agree on when.

Riding home in a taxi at 9:30 on a Wednesday night, I knew I was in trouble when I heard a voicemail message from Emily saying she’d forgotten her keys and would be waiting for me at the Starbucks near our apartment. What I didn’t know was how much trouble.

Sweeping into the coffee shop, I offered the breeziest of apologies. Emily was not charmed.“I’ve been waiting here for two hours,” she fumed. “It’s not my fault you forgot your keys,” I retorted—reasonably enough, I thought.On the walk home, I rolled out the excuses. I’d been at a work party, a networking thing. The music was loud, and I didn’t hear the phone ring. I was on my way out when I ran into someone I knew. And so on. She wasn’t having any of it. “You smell like liquor,” she groused.Back at our apartment, the argument continued, to my astonishment.

If it had only been the one time, it would be one thing, Emily informed me. But I’d been out every night in the previous two weeks (this was only a mild exaggeration). Then came the punch line: “How are we supposed to have a baby in a few months if you never even come home after work?” Aha! I thought. So that’s what this is about. I should have known. When you’re 30 years old, like we are, and when you’ve been married three years, like we have, everything becomes about having a baby. No matter what we’re talking about—our jobs, our friends, an upcoming vacation—reproduction is always just a free association away. It has even infiltrated our sex life: