Thinx, which sells menstruation underwear, recently submitted a proposal for the New York City subway system featuring an advertisement referencing menstruation. But Outfront Media, which manages a lot of the Metropolitan Transportation Authority's ad campaigns, turned down the proposal. It stated the ads "seem to have a bit too much skin," among other issues. Here is a photo of the rejected ads:

Thinx co-founder Miki Agrawal told Mic's Jenny Kutner in an exclusive interview that the ads were intended to challenge the universal stigma surrounding menstruation, making the ultimate rejection that much more troubling.

One of the ads includes a grapefruit, which Agrawal acknowledges might look like a vagina at first glance but is "clearly a grapefruit" when you get a closer look. Another ad depicts an egg yolk, a symbol of the unfertilized eggs that leave a woman's body when she menstruates every month. These images plus the mention of the word "period," however, concerned Outfront Media.

Though Outfront was also worried about copyright issues, the company told Agrawal in an email obtained by Mic that the ads had "a bit too much skin" and that the eggs and grapefruit seemed "inappropriate."

"I stated [to an Outfront representative] that it was extremely disheartening that [certain other ads] could fly, but something for women that speaks directly to women isn't OK by them," Thinx director of marketing, Veronica del Rosario told Mic. "He replied, 'This is not a women's issue. Don't try to make it a women's rights thing.'"

Thinx knew going into the proposal that the company would have to honor the MTA advertising guidelines, which do not allow ads promoting "sexual or excretory activities" or a "sexually oriented business." Of course, that hasn't stopped other sexually charged ads from appearing in New York subways:

Menstruation is often stigmatized.

Even though menstruation is a natural part of being a woman, some still get squeamish at the thought of periods. During the first Republican presidential debate in August, Donald Trump received ample criticism on social media for saying Fox News host Megyn Kelly had "blood coming out of her... wherever" when she called out his past treatment of women. He went on to say that he was not, in fact, referencing Kelly's menstrual cycle, but many still felt he perpetuated the taboo surrounding menstruation in our country.

Earlier this year, ATTN: covered the challenges many homeless women endure during their monthly menstrual cycles. Molly Moen, COO of the Downtown Women's Center in Los Angeles, previously told ATTN: that she has seen many homeless women struggle with this. She also said it doesn't help that menstruation is already so stigmatized in our culture.

"[I]n general, it's one of those things that people don't talk about very much," Moen told ATTN:. "Certainly not in very formal settings. [Women] have very distinct needs and we really do need to be paying attention to them, even if they are things that folks are sometimes uncomfortable talking about."