"Are you ready to talk about vaginas?" Gwyneth Paltrow asked in episode 3 of Netflix's "The Goop Lab." Determined to make Paltrow's error into a teachable moment, the late prolific sex educator Betty Dodson quickly set the facts straight.

"The vagina's the birth canal only," Dodson asserted firmly. "You want to talk about the vulva, which is the clitoris and the inner lips and all that good s$%t around it."

Surprised and slightly embarrassed by her apparent lack of knowledge, Paltrow followed the explanation by admitting she thought "the vagina was the whole [thing]" and has always referred to it as such. And that, it turned out, was one of Dodson's pet peeves.

As I listened to Paltrow, the owner of a successful, albeit controversial, wellness and lifestyle brand for women, make such a simple mistake about female anatomy—one I'd heard over and over again—I immediately wondered how many vulva owners had the same misconception. And why didn't I ever hear anyone actually use the word "vulva"?