Today I am 34 weeks, 2 days pregnant with the mystery child that & has dubbed “Ermentrude.” I can’t get that name, or any other, to stick to her. He’s way ahead of me, having already chosen the name we’ll give her once she’s born. I’m not convinced that his choice is actually her name, but she is maddeningly refusing to suggest any alternatives. In conversation with Natalie I’ve taken the path of least resistance and dubbed the reticent fetus “Baby Sister,” thereby crossing a boundary that I’d hoped to avoid.

I did not want to define this child in relation to Natalie.

I’m an only child. There were periodic visits from cousins and distant stepsiblings, but functionally, I grew up as the single member of my generation, the sole and unique offspring shuttling back and forth between parents who had long since declared their independence from each other. The family “unit” was me.

Make no mistake — this was awesome. I loved life at the center of my own universe. Perhaps I might have been a better friend, less results-obsessed, and less of a pain in the ass in general, had my self-esteem been subject to the balancing gravitational effects of siblings. But throughout my formative years, I never regretted their absence. Family was a zero-sum game to me; there seemed to be a finite emotional and financial reserve to subsidize the great doings of my adolescence, and I was not prepared to share.

(Although, in the interest of full disclosure, I will confess that in my late teens I half-wished I’d had a twin brother — if only to spare me the embarrassment of learning, at age sixteen, that male genitalia were actually located several inches north of where I’d suspected them to be.)

So I never imagined deliberately attempting to have more than one child. Twins seemed to me to be the perfect solution if you wanted kids, plural; you’d neatly avoid the inherent inequity of an age disparity, or the inevitable shifting of familial attentions when a sequel arrived to disrupt the solo act. But if your first pregnancy produced a single child, ah well, then you were done, weren’t you? Unless you wanted to send all kinds of undermining and sabotaging messages to your firstborn. You did not complete our family. You were insufficient. You were not worthy of 100% of our attentions. And the Biblical injunction that, for decades, has episodically drifted through my own nightmares: you have been measured and found wanting.

So much of life, it seems, is measured. For well beyond the first half of my life, my performance at the tasks appointed to me was precisely tracked by letter grades, grade-point averages, class ranks and test scores. I both relished and resented this: it was nice to know exactly where you stood by some objective measure (a clarity which eluded me in the vast majority of my interpersonal relationships), but it rankled, too, that so many intensely life-altering outcomes depended so completely on these stupid numbers, this denatured distillate of actual accomplishment. I tortured myself to the verge of insanity in law school to make my required numbers, and then promised myself that I’d never let them own me again.

Of course it came up after my first child was born. Before they’d even finished suturing my second-degree tear, I piped up “Well, that wasn’t so bad! Let’s do that again,” and meant it only half in irony. All the horror stories I’d heard about pregnancy and childbirth had just been patently disproven by my own implausible experience. Natalie’s pregnancy was dreamy-wonderful, and while it hurt plenty, precipitous labor is totally the way to go. To the extent that the misery of growing and pushing out a baby was supposed to be a disincentive to do so again, I had just lost a reason to Stop At One.

But but! The measuring thing! Would it not be a disservice to my brilliant firstborn — who continued to buck all predictions by being on impossibly good behavior throughout her infancy, sleeping beautifully and smiling constantly and barely protesting at my ultimately-futile attempts to breastfeed — to foist a sibling on her? To refocus the spotlight that so justifiably illuminated Natalie, and only Natalie, the first child and first grandchild, the complete and total rock star who was doing all the right things to earn all the attention she was getting?

My reaction surprised me. What I was feeling was greed. Natalie was so wonderful — and growing up so quickly — that I wasn’t done yet. I wanted more. The lust to cuddle a newborn returned almost immediately after Natalie outgrew her breastfeeding-failure scrawniness. The itch to be pregnant again, to feel that astral-nerve connection to another person wholly contained within your own, resurfaced soon after I lost the baby weight. And to my surprise, the strongest urge toward the decision came from the need to dispel the fog of war with respect to our future family and home life. Too many imminent life-choices depended on the number of children we ultimately planned to have. And I was already 37, so our window of opportunity was narrowing daily.

I won’t say that it was without reservation that I marched back in to Dr. Butler’s office, requesting a refill on the pharmaceutical cocktail that had produced Natalie. But the enthusiasm definitely outweighed the reservations, and when the tests came back positive, the reservations departed altogether. We were having a second child. So many ambiguities and unresolved issues now had their answer made clear.

Except, that is, for the child herself. Baby Sister has spent this pregnancy behind a veil of secrecy, refusing to hint at her gender or desired name, coyly kicking and squirming and poisoning her mother’s mental health with a sauce of crazymaking pregnancy hormones. (Please, please please don’t let the downswings of this pregnancy be any sort of omen of the kind of infant she’ll be.) This has decidedly not been a repeat of my first, ideal, let’s-do-this-again pregnancy. My fondest hope had been to bond with this kid just as I’d done with her big sister, for the forty weeks prior to her birth. But other than an ultrasound glimpse of Baby Sister’s face (which bore a breathtaking resemblance to newborn Natalie’s), and one beautiful musical handshake, I still don’t feel that I know her at all.

And when you can’t reach the essence of something, you resort to comparative measures. The Measuring Thing is inescapable that way. This child has rebuffed our best attempts at unique identifiers: neither “Oberon” nor “Baby Danger” nor “Ermentrude” has stuck, leaving only those descriptors that define her in relation to other people. Our Second Daughter. Baby Sister. The riddle wrapped up in a mystery inside my midsection, who will, in five or six weeks, emerge and finally introduce us to the person we have been so thoroughly unable to anticipate.

In her defense, I have been feeling better lately. Ever since the concert last month I’ve been lighter on my feet, sleeping better, less paranoid that I’m about to suffer a catastrophic work-related meltdown or car accident or some such smiting. I’m still nervous that this kid will come out *difficult* in a way that Natalie wasn’t, in a way that we are ill prepared to manage. But I’m also starting to make peace with that thought. Maybe she’ll keep us up at night. Maybe she’ll be colicky and refluxy. Maybe she’ll cry irrationally and we won’t know how to get her to stop. But at least she’ll be here, she’ll be someone we can get to know and come to understand. She’ll be her own person, and not just Baby Sister.

And for that, I can’t wait.