With hetero couples, it's pretty obvious who does the childbearing. But lesbian couples who choose to carry their own child face a quandary: Which partner gets preggers?

That's the question Callie (Sara Ramirez) and Arizona (Jessica Capshaw) are facing in this sneak peek of Grey's Anatomy Season 10, Episode 20 — "Go It Alone," airing this Thursday, April 17 — as they flip a coin to decide who will get knocked up.

Wait, a coin flip? Really? Even Callie is incredulous.

"You don't think this is silly?" she asks her one-legged wife. "Because we're not picking a movie or takeout. This is — it's a bigger deal."

"Yeah!" Arizona responds. "This feels right! I mean, flipping a coin feels right. It feels decisive. It's done, it's—"

"Fine-fine-fine." Callie interjects. And she tosses the coin into the air.

Of course, this just being a sneak peek, we don't actually see how the coin lands. We'll just have to wait until Thursday.

For the record, both women have gotten pregnant, and neither pregnancy went well. Pregnant Callie was thrown from a car, though baby Sofia miraculously survived. And Arizona's pregnancy ended in a miscarriage, as we found out long after the fact. (We're still angry about that.)

So perhaps a coin flip is indeed the fairest way of determining who goes through the ordeal again. But Judging solely on the number of times they Callie and Arizona utter the words "right" and "OK," we have a feeling that this tie-breaker will end up being neither "right" nor "OK" to both parties.

What do you think will happen? Speculate away in the comments below!

Grey's Anatomy Season 10, Episode 20 — "Go It Alone" — airs Thursday, April 17, at 9 p.m. ET.


Dan Clarendon is an assistant editor at Wetpaint Entertainment. Follow him on Twitter and Google+!