1. Petitioning for restraining orders against abusers.
Yes, you read that correctly. A 2015 study that looked at 3,923 women who had petitioned for a civil restraining order between January 1996 and December 1999 found that women lose anywhere between $312 and $1,018 dollars in the year after seeking court assistance. It may seem counterintuitive -- since studies show that petitioning actually does promote women's safety, which could potentially lead them to work more hours or find higher-paying jobs -- but the researchers found compelling evidence that the vulnerability and hardship women experience just after petitioning can lead to the aforementioned financial blow.
2. Not being thin enough.
Attractiveness can influence earnings for both men and women, but societal beauty standards seem to hit women's wallets the hardest. Data from the 2004 National Longitudinal Survey of Youth showed that overall average annual incomes were $4,772 less for obese men and $8,666 less for obese women compared to "normal weight" workers.
3. Getting married...
Marriage is generally a cause for celebration, but it doesn't always spell out individual financial gain for women (if you discount their partners' income). The longitudinal Study of Mathematically Precocious Youth followed 1,650 highly intelligent kids for 40 years. While most participants saw incredibly fruitful careers, male participants made significantly more money than female participants, and married men earned even more once they tied the knot. Women, on the other hand, saw no boost in income after marrying -- they generally made personal life choices to maintain their family at the expense of their careers.
4. ...And having children.
Often related to marriage, the "mommy tax," a term coined by author Ann Crittenden in 2010, refers to the lower wages women are paid after having children. Crittenden estimated that a college-educated woman could lose about a million dollars in lifetime earnings after just one child. Many studies have linked motherhood with lower pay, but it's tricky to nail down why. Perhaps the lower earnings are due to mothers being less productive at work, choosing more flexible roles or lacking experience due to time spent with children. But many studies also support the idea that some employers may be discriminating against mothers. Fathers, on the other hand, tend to see a boost in income.
5. Working for a man.
In a 2014 study of 23,000 high-level corporate employees, researchers found that officers got paid less if the CEO of the company was of the opposite gender. However, women suffered the most, since older male CEOs had "the greatest propensity to differentiate on the basis of sex." On average, female participants earned $2,960 less than their male peers annually, but the women who worked for male CEOs earned $46,500 less per year than men in similar roles. The study also found that women got smaller raises if a company was headed by a man.
6. Not being white.
The wage gap widens when you factor in race, according to 2013 stats from the U.S. Census Bureau. While white women were paid 78 percent of what white men made that year, Hispanic and Latina women only earned 54 percent compared to their white male counterparts. African-American women saw a slightly narrower gap -- but still lower than that of white women -- at 64 percent. (For what it's worth, Asian-American women experienced the smallest wage gap in 2013, earning 90 percent of what white men made.)
7. Just being a woman.
The bad news is that women may have to wait until 2058 to see an end to the gender wage gap. The good news? Your celebratory wine will have some time to properly age by then.