Our attitudes about sex have changed pretty drastically in the past 40 years

We've come a long way since the days of "I Love Lucy" when the idea of sex on TV was so taboo that even married couples were shown sleeping in separate beds.

Since then, our ideas about sex have opened up a lot - we've become far more accepting of everything from sex before marriage to sex between same-sex couples, and those trends have picked up pace since the 1970s.

But in a few areas, like sex outside of marriage, we've actually grown a tad less accepting.

At least that's according to a recent study in the Archives of Sexual Behavior which looked at data from a huge sample of Americans included in the General Social Survey (GSS).

Here are its biggest findings:

We've grown more accepting of sex before marriage

In the early 70s, just 29% of Americans (35% of men and 23% of women) thought it was okay to have sex before your wedding day. To be more exact, when given options on a scale of 1-4, with 1 being "always wrong," and 4 being "not wrong at all," less than a third of people would choose "not wrong at all."

About a decade later, this percentage grew to around 42%, where it stayed through the 90s. In the 2000s, it rose to nearly half (49%), and in the 2010s it hit 55% (59% of men and 52% of women).

We've grown more accepting of gay and lesbian sex

Acceptance of sex between gays and lesbians has tripled since the 70s, with the most growth happening amongst young people. Just over 1 in every 5 young people who were between 18 and 29 in the 1970s said sex between people of the same gender was "not wrong at all." By the 90s, this percentage rose to 26%. By the 2010s, more than half of Millennials (56%) approve of sex between same-sex partners.

and...

We're reporting having more sexual partners

In the 1980s, people said they had an average of 7 sex partners since age 18 (roughly 11 for men and 4 for women). In the 2010s that number rose to 11 (roughly 18 for men and 6 for women).

We're reporting having more casual sex

Just about 35% of 18-29 year olds in the late 1980s said they had sex with a casual date (44% of men and 19% of women). Yet nearly half (45%) of Millennials in the 2010s (55% of men and 31% of women) said they'd had sex with a casual date.

These increases don't necessarily mean we're simply having more casual sex or sex partners, and could also be a result of people being more comfortable about admitting they've had more casual sex or sex partners in the first place.

but...

We've grown less accepting of sex outside of marriage

In the 70s, about 81% of people said they were accepting of sex between two people who were married to other people. That figure declined to 67% in the 90s and by the 2010s fell a bit more to 65%.