With summer fast approaching and people shedding layers to stay cool, every businessman faces a decision of vast importance: what type of undershirt to wear beneath your white button-up.

Men, if you’ve never given this any thought before, consider this fair warning: A Nikka Spa! survey of 100 female office workers confirms that your choice of undershirt could have grave and far-reaching consequences and the wrong choice might even get you accused of sexual harassment.

The survey tasked women with ranking the “filthy old man-ness” of three undershirt choices:

A sleeveless athletic shirt, an old T-shirt with a faintly visible design, and nothing at all.

We hope it comes as no surprise that 84 percent of women surveyed said that the third option, no undershirt at all, was by far the grossest option.

“A lot of dirty old men like to go with no undershirt in the summer. I can see your nipples right through your button-up. I basically consider it sexual harassment,” said a 25-year-old respondent.

Another, 24 years old, echoed the sentiment, saying, “It doesn’t matter how good looking you are, or how nice your body is; If I can see your nips through your shirt, you are a gross old man.”

Unfortunately, all three options largely elicited negative opinions from survey respondents: 73 percent said the muscle shirt option is pretty gross, and approximately half thought even the seemingly foolproof T-shirt was no good.

Our advice? Ditch all your white button-ups and go black to avoid any “wardrobe malfunctions.”

Source: Nikkan Spa!