When a person is described as sexy, they're interesting in a romantic or arousing way. A sexy song might be incredibly romantic, made for slow dancing, or an ad might tout sexy shoes that look amazing and will be the envy of all your friends. The word sexy is often used more broadly to refer to appealing or enticing things — clothes, cars, even ideas. Before sexy was coined, around 1905, the equivalent word was sexful.
Biologists studying evolution propose several explanations for why sexual reproduction developed and why it is maintained. These reasons include reducing the likelihood of the accumulation of deleterious mutations, increasing rate of adaptation to changing environments, dealing with competition, DNA repair and masking deleterious mutations. All of these ideas about why sexual reproduction has been maintained are generally supported, but ultimately the size of the population determines if sexual reproduction is entirely beneficial. Larger populations appear to respond more quickly to some of the benefits obtained through sexual reproduction than do smaller population sizes.
In some religions, sexual behavior is regarded as primarily spiritual. In others it is treated as primarily physical. Some hold that sexual behavior is only spiritual within certain kinds of relationships, when used for specific purposes, or when incorporated into religious ritual. In some religions there are no distinctions between the physical and the spiritual, whereas some religions view human sexuality as a way of completing the gap that exists between the spiritual and the physical.
The phrase “sexual health” encompasses a range of public health and clinical issues related to prevention of sexually transmitted infections. I use the phrase a lot in my own work and its widening currency is a welcome new paradigm in our field. In fact, the concept of sexual health seems to me of fundamental relevance to all aspects of prevention of sexually transmitted infections.
Before the High Middle Ages, homosexual acts appear to have been ignored or tolerated by the Christian church. During the 12th century, hostility toward homosexuality began to spread throughout religious and secular institutions. By the end of the 19th century, it was viewed as a pathology. Havelock Ellis and Sigmund Freud adopted more accepting stances; Ellis said homosexuality was inborn and therefore not immoral, not a disease, and that many homosexuals made significant contributions to society. Freud wrote that all human beings as capable of becoming either heterosexual or homosexual; neither orientation was assumed to be innate.[page needed] According to Freud, a person's orientation depended on the resolution of the Oedipus complex. He said male homosexuality resulted when a young boy had an authoritarian, rejecting mother and turned to his father for love and affection, and later to men in general. He said female homosexuality developed when a girl loved her mother and identified with her father, and became fixated at that stage.[page needed]
“Don't think that adding sex toys means that your sex is boring or less than satisfying,” says sex expert Laurel House. “The opposite is actually true! It shows you're open to exploring many avenues of pleasure because you feel safe and simultaneously liberated within your relationship. The key is to communicate with your partner. Talk about what you would like to try, then have a conversation after you put your new toy to use to honestly discuss if you liked it and if you want to try it again.”
These shifts coincide with another major change: parents’ increased anxiety about their children’s educational and economic prospects. Among the affluent and educated, especially, this anxiety has led to big changes in what’s expected of teens. “It’s hard to work in sex when the baseball team practices at 6:30, school starts at 8:15, drama club meets at 4:15, the soup kitchen starts serving at 6, and, oh yeah, your screenplay needs completion,” said a man who was a couple of years out of college, thinking back on his high-school years. He added: “There’s immense pressure” from parents and other authority figures “to focus on the self, at the expense of relationships”—pressure, quite a few 20-somethings told me, that extends right on through college.
Sex seems more fraught now. This problem has no single source; the world has changed in so many ways, so quickly. In time, maybe, we will rethink some things: The abysmal state of sex education, which was once a joke but is now, in the age of porn, a disgrace. The dysfunctional relationships so many of us have with our phones and social media, to the detriment of our relationships with humans. Efforts to “protect” teenagers from most everything, including romance, leaving them ill-equipped for both the miseries and the joys of adulthood.
Many insects use a sex determination system based on the number of sex chromosomes. This is called X0 sex-determination—the 0 indicates the absence of the sex chromosome. All other chromosomes in these organisms are diploid, but organisms may inherit one or two X chromosomes. In field crickets, for example, insects with a single X chromosome develop as male, while those with two develop as female. In the nematode C. elegans most worms are self-fertilizing XX hermaphrodites, but occasionally abnormalities in chromosome inheritance regularly give rise to individuals with only one X chromosome—these X0 individuals are fertile males (and half their offspring are male).
No genes are shared between the avian ZW and mammal XY chromosomes, and from a comparison between chicken and human, the Z chromosome appeared similar to the autosomal chromosome 9 in human, rather than X or Y, suggesting that the ZW and XY sex-determination systems do not share an origin, but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor of birds and mammals. A paper from 2004 compared the chicken Z chromosome with platypus X chromosomes and suggested that the two systems are related.
Slangs for oral sex is common in Western cultures, for example: "going down on", "giving a blowjob", "giving head", or "eating out". The technical term for oral sex is fellatio if performed on a male and cunnilingus if performed on a female. When a man performs fellatio on himself, it is called autofellatio, and autocunnilingus if a woman performs cunnilingus on herself. Few men and women are able to do this.
Technique: The most commonly used position in the world, the missionary is an especially intimate position allowing for face-to-face contact. You like it because you can control penetration depth and speed of thrusting. She enjoys feeling your weight on her body, and the maximum skin-to-skin contact. Note that this position can make it more difficult to hold off ejaculation because of the intense friction and deep thrusting. To lengthen lovemaking, start there then switch to a position that maintains clitoral pressure without so much pelvic back and forth.
Technique: This is an ideal position if she is pregnant or either one of you had a knee injury because it keeps weight off the body. To get into the position, begin by lying on your sides and facing one another. She spreads her legs slightly to allow you to enter her, then closes her legs so the part of your shaft that's outside can press against her clitoris. It's easy to kiss from this intimate face-to-face position.
At least for humans, this most basic of acts is anything but basic. As the pioneering sex researcher Alfred Kinsey put it, the only universal in human sexuality is variability itself. From attraction to action, sexual behavior takes many forms. Human interest in sex is not a matter left to chance but more a built-in imperative; survival of the species depends on it. The decks are stacked in sex's favor, as a passport to bonding, to intimacy, to pleasure, and even to human growth and healing. Bodies and interests change over the course of time, and the complexities of physiology and psychology mean that most people experience a sexual problem at some point in their lives. Although sex can be one of the most difficult topics for partners to discuss, it's one that also stands to draw couples closer together. The moral and political implications of sex vary greatly from culture to culture, and even within cultures and over time; still, there is agreement on one certainty: It's why we're alive today and what future generations depend on.