Female breasts are usually the object of fixation for men upon first meeting women of all different shapes and sizes. Men ogle at a woman’s cleavage because they tend to look first at her body, and spend less time looking at her face. They draw their attention to the waist, breasts, and hips. While men continue to satisfy their male compulsion by looking at cleavage, the folks over at BuzzFeed compiled nine jaw-dropping facts that may change how men, and perhaps women, stare at breasts.

1. Humans are the only species to have permanently enlarged breasts.

2. We don’t know why heterosexual men love breasts. They could be a signal of fertility or, as studies suggest, breasts may help couples bond.

3. Breasts are dangerous to men’s brains. In a study, men that first viewed images of top-heavy women performed worse on cognitive tests.

4. The average bra size is 34DD in the U.S. Twenty years ago, the average bust was 34B.

5. No two breasts are the same size. Usually, the one on the left is bigger.

6. Breast milk has substances closely related to marijuana, suggesting this could be linked to the soothing effect it has on newborns.

7. Breast augmentation is the most popular cosmetic surgery in the U.S.

8. While breast augmentation continues to rise in the U.S., studies show financially stable men prefer smaller breasts.

9. Go topless day is usually in August. Specifically on Sunday, August 24 this year. Mark your calendars!