As citizens of the 21st century, what has become commonplace in modern society is the result of continuous cultural changes in the way we live and think, inspired by leaders who were fundamentally ahead of their time.

In an ode to progress, we’ve partnered with SHOWTIME® Original Series, MASTERS OF SEX to bring you 9 facts about modern life and relationships that would have seemed unimaginable 50 years ago.

1. Not all “households” consist of married couples.

According to Unmarried.org, 45 percent of all households in the U.S. consisted of unmarried couples in 2010. In fact, in 2000, there were ten times the amount of unmarried couples living together as there were only forty years earlier.

2. Women are now more educated than men.

In 1970, only 12 percent of 25 to 32-year-old women had a college education, compared to 20 percent of men in the same age group. Now, 38 percent of these women hold college degrees, compared to only 31 percent of men. The cross-over took place between 1990 and 2000, a time when women took on the third wave of feminism and revisited their relationship to power and the work place.

3. Unmarried mothers are on the rise.

According to the National Center for Health Statistics, “39.7 percent of all births are to unmarried women.” This is a drastic leap from the 1950s-1960s, when it was only an estimated 500,000 women that became unmarried mothers.

4. People are becoming less squeamish about their sexual fetishes.

In 2001, 70,000 adult websites existed. In 2013, that number climbed to more than 4.2 million in just the US alone.

5. Forty-four percent of millennials say that marriage is becoming obsolete.

In 2011 survey, more than four in ten American adults between the ages of 18-29 said the institution of marriage is becoming obsolete. Comparatively, author and New York Times contributor Mary Cantwell’s reflected on marriage trends in the 1950s, saying that getting married young was like “getting a sale on the first day.”

6. One-third of married couples meet online.

While most millennials feel that marriage is waning in significance, that hasn’t stopped them from taking to the web to meet their match. A recent study found that of people who got married between 2005 and 2012, more than one-third began dating online.

7. Mothers are the primary breadwinners in 40 percent of U.S. households.

Image via Giphy

A 2013 report revealed that mothers were the primary income providers in 40 percent of U.S. households — nearly 4 times as many as in 1960. What’s more, two-thirds of women who had their first baby between 2001 and 2003 worked during their pregnancy, and 80 percent of those women worked within one month or less of giving birth. Compare this to the period between 1961 and 1965, when 44 percent of women worked while pregnant with 35 percent working one month or less before delivering.

8. Same-sex marriage is legal in 19 U.S states and the District of Columbia.

While LGBTQ Americans have been lobbying for marriage equality since the early 1960s, it wasn’t until recent years that this debate began to take the national center stage. Today, 19 states (in addition to Washington, DC) legally recognize same-sex couples’ right to put a ring on it by law.

From A to Z: California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Oregon, Pennsylvania, Rhode Island, Vermont and Washington.

9. Sex is a beautiful thing.

In the late 1950s and 60s, when the subject was taboo, research duo William H. Masters and Virginia E. Johnson pioneered the scientific study of human sexuality. They established sexuality as a healthy, human trait and created greater social acceptance for experiencing pleasure and deep intimacy from sex.

Pioneers like Dr. William Masters and Virginia Johnson inspired cultural changes that influenced popular conceptions of gender roles, relationships, and sex that ultimately contributed to the progressive present we live in today. Based on the provocative true story of Masters & Johnson, the highly acclaimed SHOWTIME® Original Series, MASTERS OF SEX, returns for a groundbreaking new season. Tune in for the Season 2 premiere Sunday, July 13 at 10PM ET/PT, only on SHOWTIME®.