We're constantly reminded of sex, whether by a sultry magazine cover at the newsstand, a steamy scene at the movies, or a night at the bar. Science got its hands dirty this past year trying to unravel the latest patterns and trends in the field of sex research, a popular and often controversial area of interest. Here's what we learned.

Sex: Why It Feels So Good

Many people will admit they love sex because it feels so good. It’s a source of pleasurable sensations that facilitate an emotional connection between two people, but science has found it’s also an altered state of consciousness. A study in Socioaffective Neuroscience & Psychology found sexual pleasure floods the brain with a surge of neurochemicals — chemical messengers that forge emotions, feelings of attachment, and even love. The level of pleasure that’s felt is linked to the release of chemicals, which can be used to measure the intensity of an orgasm.

We discovered that if sexual stimulation is intense enough, and goes on long enough, synchronized activity could spread throughout the brain. This intense focused attention outcompetes usual self-awareness for access to consciousness, and so produces a state of sensory absorption and trance.

Read More: How The Brain Functions During An Orgasm

So, how long should this euphoric-like state last?

In an article for The Conversationalist, Dr. Brendan Zietsch, a psychologist from the University of Queensland, focused on how long heterosexual couples report penetrative sex actually lasts. The findings revealed the average time for each couple, across all the times they had sex, ranged from 33 seconds to 44 minutes. Meanwhile, the average across all couples was 5.4 minutes. This means a couple will typically go for an average of 5.4 minutes every time they have sex. Zietsch suspects penis shape could influence how long men last in bed.

Who's Getting It On Vs. Who’s Not

Sexless Millennials

Dating apps like Tinder, frequently used by Millennials, have led casual sex to become more common. Naturally, we would assume Millennials are having more sex, but a study in Archives of Sexual Behavior found more young people are living sexless lives than their counterparts born in the 1960s did at the same age. However, this does not mean a vast majority of young Millennials are having less sex than previous generations. It just means that the amount of people born in the early 1990s who are not having sex is larger than a similar cohort from previous years.

Sex In The “Golden” Years

Many believe once you get older, the sex becomes less and less frequent until it comes to a halt. This year, researchers have noted older adults are having more sex, and they agree it does get better with age. A survey conducted by the University of Guelph and the Sex Information and Education Council of Canada (SIECCAN) found older couples are starting to be active and get creative by adopting new positions and activities. People over 40 are still having sex, and becoming more adventurous in bed with more than half admitting they were more interested in trying new things to boost pleasure than they were a decade ago.

The elderly also continue to be sexually active, and consider sex essential to their well-being, happiness, and overall quality of life, especially after retirement. Some older adults abstain from sex due to health conditions, or loss of interest, but others refused to renounce it.

The concept of sex is pretty straight forward, but when it comes to the female orgasm, science is still figuring out one of the greatest mysteries.

Women And Sex

The Female Orgasm: Hot Spots Of Pleasure

New research pinpoints there's a new understanding of the female orgasm: It incorporates the external clitoral glands, the internal region around the G-spot that corresponds to the internal clitoral bulbs, the cervix, and the sensory stimulation of non-genital areas, such as the nipples. In other words, it’s the stimulation of one or various erogenous zones that induces pleasure and orgasm during masturbation and sexual intercourse.

Read More: Erotic Hypnosis For Sexual Climax With Mind Control

Researchers believe orgasms don't have to come from one site, nor from all sites, and most importantly, they don't have to be the same for every woman, nor for every sexual experience the woman has to be considered whole and valid. Orgasms are a very individual and subjective experience.

Female Orgasm Can Boost Fertility

Evolutionary biologists have debated the purpose of the female orgasm beyond just sexual pleasure. A study found orgasms could potentially boost fertility by as much as 15 percent. It performs some sort of “sperm-retention function,” meaning it could act as a suction to “suck up” semen into the vaginal canal. However, there are conflicting studies that debate whether the female orgasm has a biological purpose.

Women Receive Less Oral Sex

Not all is fair in love and oral sex. A study in The Canadian Journal of Human Sexuality found women are more than twice as likely to go down on their partners than men, but they are less likely to enjoy performing the act. The biggest gender difference in oral sex was the enjoyment of giving oral. More than half of men who had given cunnilingus reported enjoying it a lot, while an additional 41 percent enjoyed it somewhat, and 7 percent didn't enjoy it much or at all. Contrastingly, only 28 percent of the women who gave fellatio found it very pleasurable; for 55 it was somewhat pleasurable; and 17 percent didn't enjoy doing it. The findings suggest equal reciprocation could satisfy both partners.

Read More: Does 'Going Down' On Your Partner Have Biological Roots?

Sex In Relationships

Good Sex In Long-Term Relationships

Couples often get into a rut about sex being boring and predictable, but great sex is possible in long-term relationships. A recent study in the Journal of Personality and Social Psychology found long-term couples can reignite the spark, and have better sex, by being responsive to each other. Partners who are responsive to each other outside the bedroom are able to maintain their sexual desire.

More Sex Leads To Positive Feelings About Partners

Unsurprisingly, the more sex we have with our partners, the more likely we’ll begin to have more positive feelings towards them. A study from Florida State University found the frequency with which couples have sex has no influence on whether or not they report being happy with their relationship, but their sexual frequency does influence their more spontaneous, automatic, gut-level feelings about their partners. Whether sex is happening once a month or once every few hours, it’s really about quality over quantity.

In 2016, science has taught us there are shades of grey when it comes to sex — it’s not as concrete or simple as we believe.

See Also:

Sex Once A Week Makes For A Happy Life (Unless You're Single)

Straight Women Turned On By Attractive Women Are Either 'Bisexual Or Gay', Says Study