I think it might have had more to do with the setting
Warning: Un-graphic mention of lady-doctors ahead.
I probably get told I look like Katherine Heigl an average of about 1.5 times a week. So my answer to, "has anyone ever told you you look like Katherine Heigl/that girl from Knocked Up" is yes, actually, all the time*. But this morning, my answer was given through a burst of laughter. Because you see, I was asked this by my gynecologist. While I was in the gown, and the stirrups**. And since that's the way Ms. Heigl seared her visage into mass cultural consciousness, well, I think it might have effected the comparison a bit.
*Followed by, "but you should see my friend Alyssa. She REALLY looks like her!"
**Which, they had to pull all the way out cause boy! Your legs sure are long, aren't they sweetie? Also, the nurse wrote down that I'm 7'1" on my chart. Long, but not quite that long.