Marie Holmes: When people ask 'is that baby yours?'

We have two kids, one related to each of us, and both related to Mr Anonymous. Photo / 123RF

"Is that your baby?" asked the man on the subway.

"Yup," I smiled, thinking of the triumphant moment when I arrived at the hospital and was determined to already be 10 centimeters dilated.

It wasn't the answer he was after, but there was no need to explain that.

She is my daughter. I gave birth to her. I nurse her. But she doesn't have any of my genes.

The man looked at my baby's pale yellow hair, round blue eyes and rosy skin, then at my darker features.

"Is your husband Irish or Scandinavian or something?"

"Something like that," I said, stifling a laugh.

It was rude of him to ask, but in the context of the lifetime of white privilege I've accumulated, it was more funny than painful.

My partner, Sarah, who provided the egg for this pregnancy, is mostly Norwegian. Our sperm donor, who we selected before conceiving our 5-year-old son, is also of Scandinavian and Northern European descent. So baby Olive looks like a fat-cheeked Botticelli angel. And, frankly, bears no resemblance to me at all.

Our son Max was conceived with my egg on a second round of IVF after every other method of lesbian conception, from baby medicine syringe (not actually a turkey baster) to medicated intrauterine insemination had failed us numerous times.

I didn't really want to go through all of that again. I also desperately wanted to be pregnant another time.

Sarah didn't want to be pregnant, but eventually she decided that she did want to pass along her genes. So that some piece of her would live on in the world after she is gone, but also out of simple curiosity. What would her child look like? Who would she be?

When most people choose an egg donor, it's a decision borne from a lot of loss and grief. But for us, it was really just for kicks. Given my poor fertility, we were going to take on more debt to do the IVF either way.

Amazingly, it worked. We have two kids, one related to each of us, and both related to Mr Anonymous.

Max has my eyes, but he has Sarah's taste for pickles and smoked fish, her tenacity and her ability to summon humor under duress. Their connection is much stronger than shared genetics. Sarah is the one who can magically soothe his disappointment, calm him from the abyss of a tantrum, and entertain him through a too-long wait.

And I've learned since Olive's birth that there's something freeing about loving a child who isn't related to you. I can more easily love my daughter for who she is, not for what I hope she reflects of me. I am more likely to see her in a positive light, to forgive her difficult moments, to embrace her beauty. I noticed shortly after she was born that when people remarked that Olive was adorable, I would simply agree, where as when they said the same of Max I felt obliged to thank them. I wondered, how many of my reactions to Max's behavior, or people's impressions of him, are really about me and my own insecurities?

Sarah and I aren't too bad-looking, but there's no escaping the obvious: the donor must be very handsome. It is humbling how much more they resemble each other, this stranger, than they do us. It serves as a reminder that they don't actually belong to me. They belong to themselves and will each write their own story. For me, central to the tale of Olive's birth is that I did not have an epidural, but it seems unlikely that will have as much meaning to her as the fact that Sarah held her first, or that a family friend was able to meet her that day only because a storm had canceled her flight out of town.

Likewise, they will each determine what of the donor, and of us, they carry with them. Their light coloring, obviously, comes from him_and, in Olive's case, Sarah. But is Max's love of ice-cream from me, the donor, or neither one of us? What about his imagination, or his temper? It will be a project of self-invention, mostly out of my hands. And one of the most significant decisions, whether they want to meet the donor when they turn 18, is up to them entirely.

Not long from now, the questions from strangers on the subway won't be directed at me. They'll come straight at Olive. Am I really her mother? Is it essential to note that I gave birth to her, or that she shares half of her other parent's genes and half of her brother's? I'd be lying if I said I didn't care how she responds. Being identified as anything less than her full, true mother would break my heart. I realize, though, that the answers to these questions may depend on who is asking and may shift as time passes, and that, ultimately, they are hers to uncover and interpret.