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,[11] dealing with competition, DNA repair and masking deleterious mutations.[12][13][14] 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.[15]
Ovulation is based on a monthly cycle; the 14th day is the most fertile. On days one to four, menstruation and production of estrogen and progesterone decreases, and the endometrium starts thinning. The endometrium is sloughed off for the next three to six days. Once menstruation ends, the cycle begins again with an FSH surge from the pituitary gland. Days five to thirteen are known as the pre-ovulatory stage. During this stage, the pituitary gland secretes follicle-stimulating hormone (FSH). A negative feedback loop is enacted when estrogen is secreted to inhibit the release of FSH. Estrogen thickens the endometrium of the uterus. A surge of Luteinizing Hormone (LH) triggers ovulation. On day 14, the LH surge causes a Graafian follicle to surface the ovary. The follicle ruptures and the ripe ovum is expelled into the abdominal cavity. The fallopian tubes pick up the ovum with the fimbria. The cervical mucus changes to aid the movement of sperm. On days 15 to 28—the post-ovulatory stage, the Graafian follicle—now called the corpus luteum—secretes estrogen. Production of progesterone increases, inhibiting LH release. The endometrium thickens to prepare for implantation, and the ovum travels down the Fallopian tubes to the uterus. If the ovum is not fertilized and does not implant, menstruation begins.[8][page needed]
Ferns mostly produce large diploid sporophytes with rhizomes, roots and leaves; and on fertile leaves called sporangium, spores are produced. The spores are released and germinate to produce short, thin gametophytes that are typically heart shaped, small and green in color. The gametophytes or thallus, produce both motile sperm in the antheridia and egg cells in separate archegonia. After rains or when dew deposits a film of water, the motile sperm are splashed away from the antheridia, which are normally produced on the top side of the thallus, and swim in the film of water to the archegonia where they fertilize the egg. To promote out crossing or cross fertilization the sperm are released before the eggs are receptive of the sperm, making it more likely that the sperm will fertilize the eggs of different thallus. A zygote is formed after fertilization, which grows into a new sporophytic plant. The condition of having separate sporephyte and gametophyte plants is called alternation of generations. Other plants with similar reproductive means include the Psilotum, Lycopodium, Selaginella and Equisetum.

Other sources of sexual inhibition speak distinctly to the way we live today. For example, sleep deprivation strongly suppresses desire—and sleep quality is imperiled by now-common practices like checking one’s phone overnight. (For women, getting an extra hour of sleep predicts a 14 percent greater likelihood of having sex the next day.) In her new book, Better Sex Through Mindfulness, Lori Brotto, an obstetrics-and-gynecology professor at the University of British Columbia, reviews lab research showing that background distraction of the sort we’re all swimming in now likewise dampens arousal, in both men and women.


Insect species make up more than two-thirds of all extant animal species. Most insect species reproduce sexually, though some species are facultatively parthenogenetic. Many insects species have sexual dimorphism, while in others the sexes look nearly identical. Typically they have two sexes with males producing spermatozoa and females ova. The ova develop into eggs that have a covering called the chorion, which forms before internal fertilization. Insects have very diverse mating and reproductive strategies most often resulting in the male depositing spermatophore within the female, which she stores until she is ready for egg fertilization. After fertilization, and the formation of a zygote, and varying degrees of development, in many species the eggs are deposited outside the female; while in others, they develop further within the female and are born live.
Before the High Middle Ages, homosexual acts appear to have been ignored or tolerated by the Christian church.[60] 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.[60] 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.[60] Freud wrote that all human beings as capable of becoming either heterosexual or homosexual; neither orientation was assumed to be innate.[61][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.[61][page needed]
As a dude’s sexual preferences may not always be what’ll get a  lady to the finish line, some sex experts and adult performers have chimed in with the best positions that are most likely to please women. It seems that while yoga-tastic, wildly inventive advanced sex positions may be great for a change now and then, what women really want the most is simple: missionary.
As a dude’s sexual preferences may not always be what’ll get a  lady to the finish line, some sex experts and adult performers have chimed in with the best positions that are most likely to please women. It seems that while yoga-tastic, wildly inventive advanced sex positions may be great for a change now and then, what women really want the most is simple: missionary.
In my interviews with young women, I heard too many iterations to count of “he did something I didn’t like that I later learned is a staple in porn,” choking being one widely cited example. Outside of porn, some people do enjoy what’s known as erotic asphyxiation—they say restricting oxygen to the brain can make for more intense orgasms—but it is dangerous and ranks high on the list of things you shouldn’t do to someone unless asked to. Tess, a 31-year-old woman in San Francisco, mentioned that her past few sexual experiences had been with slightly younger men. “I’ve noticed that they tend to go for choking without prior discussion,” she said. Anna, the woman who described how dating apps could avert awkwardness, told me she’d been choked so many times that at first, she figured it was normal. “A lot of people don’t realize you have to ask,” she said.
Like other mammals, humans are primarily grouped into either the male or female sex,[15] with a small proportion (around 1%) of intersex individuals, for whom sexual classification may not be as clear.[16][page needed] The biological aspects of humans' sexuality deal with the reproductive system, the sexual response cycle, and the factors that affect these aspects. They also deal with the influence of biological factors on other aspects of sexuality, such as organic and neurological responses,[17] heredity, hormonal issues, gender issues, and sexual dysfunction.[18][page needed]
This year, almost 60 percent of women and 20 percent of men attending the Naval Academy said they experienced sexual harassment, according to the Defense Department report, up from 44 percent of women and 9 percent of men in 2016. Reports of sexual assault increased from 29 to 32 reports over the past two school years. The 32 reports mark the most the academy has received in more than a decade.
Organisms of many species are specialized into male and female varieties, each known as a sex.[1][2] Sexual reproduction involves the combining and mixing of genetic traits: specialized cells known as gametes combine to form offspring that inherit traits from each parent. The gametes produced by an organism define its sex: males produce small gametes (e.g. spermatozoa, or sperm, in animals; pollen in seed plants) while females produce large gametes (ova, or egg cells). Individual organisms which produce both male and female gametes are termed hermaphroditic.[2] Gametes can be identical in form and function (known as isogamy), but, in many cases, an asymmetry has evolved such that two different types of gametes (heterogametes) exist (known as anisogamy).
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.

The testicles are the male gonads where sperm and male hormones are produced. Millions of sperm are produced daily in several hundred seminiferous tubules. Cells called the Leydig cells lie between the tubules; these produce hormones called androgens; these consist of testosterone and inhibin. The testicles are held by the spermatic cord, which is a tubelike structure containing blood vessels, nerves, the vas deferens, and a muscle that helps to raise and lower the testicles in response to temperature changes and sexual arousal, in which the testicles are drawn closer to the body.[8][page needed]

Humans, bonobos and dolphins show cooperative behaviour. In many cases, this behaviour has shown better results than what an individual can achieve alone. In these animals, the use of sex has evolved beyond reproduction and has taken additional social functions. Sex reinforces intimate social bonds between individuals. Overall, such cooperation also benefits each member of the group in that they are better able to survive.

Sweet and sexy with a whole lot of swoon. I loved every bit of Laurin Blakely’s The Sexy One. I thought it had just the right amount of angst, the sort that kept your heart beating wildly without you wanting to beat your head against the wall. The characters themselves were as loveable as they come. An alpha yet considerate and compassionate male lead matched with an exuberant, intelligent, and witty heroine. The perfect match for such a perfect story line.


In their 2015 book, Modern Romance, the sociologist Eric Klinenberg and the comedian Aziz Ansari (who earlier this year became infamous for a hookup gone awry) describe Ansari’s visit to Japan seeking insights into the future of sex. He concluded that much of what he’d read about herbivore men missed the mark. Herbivores, he found, were “interested in sexual pleasure”—just not “through traditional routes.” Among Japan’s more popular recent innovations, he notes, is “a single-use silicone egg that men fill with lubricant and masturbate inside.” One night in Tokyo, Ansari picks one up at a convenience store, heads back to his hotel, and—sorry for the visual—gives it a go. He finds it cold and awkward, but understands its purpose. “It was a way,” he writes, “to avoid putting yourself out there and having an actual experience with another person.”
Ian Kerner, the New York sex therapist, told me that he works with a lot of men who would like to perform oral sex but are rebuffed by their partner. “I know the stereotype is often that men are the ones who don’t want to perform it, but I find the reverse,” he said. “A lot of women will say when I’m talking to them privately, ‘I just can’t believe that a guy wants to be down there, likes to do that. It’s the ugliest part of my body.’ ” When I asked 20-somethings about oral sex, a pretty sizable minority of women sounded a similar note. “Receiving makes me nervous. It feels more intimate than penetration,” wrote one woman. “I become so self-conscious and find it difficult to enjoy,” wrote another.
This portrait is compatible with a 2014 study finding that Millennial college students weren’t having more sex or sexual partners than their Gen X predecessors. It also tracks with data from the Online College Social Life Survey, a survey of more than 20,000 college students that was conducted from 2005 to 2011, which found the median number of hookups over a four-year college career to be five—a third of which involved only kissing and touching. The majority of students surveyed said they wished they had more opportunities to find a long-term boyfriend or girlfriend.
In complex organisms, the sex organs are the parts that are involved in the production and exchange of gametes in sexual reproduction. Many species, both plants and animals, have sexual specialization, and their populations are divided into male and female individuals. Conversely, there are also species in which there is no sexual specialization, and the same individuals both contain masculine and feminine reproductive organs, and they are called hermaphrodites. This is very frequent in plants.[8]
On the other hand, bacterial conjugation is a type of direct transfer of DNA between two bacteria mediated by an external appendage called the conjugation pilus.[30] Bacterial conjugation is controlled by plasmid genes that are adapted for spreading copies of the plasmid between bacteria. The infrequent integration of a plasmid into a host bacterial chromosome, and the subsequent transfer of a part of the host chromosome to another cell do not appear to be bacterial adaptations.[12][31]
Two animals coming together for the purposes of sexual reproduction is called mating. Most animals only mate when the female is at the point of estrus, which is the most fertile period of time in its reproductive cycle.[5][6] In certain animals, sexual intercourse is not only used for reproduction, but has taken other functions as well. These animals include bonobos,[7] dolphins,[8] and chimpanzees which also have sexual intercourse even when the female is not in estrus, and to engage in sex acts with same-sex partners.[9] In most instances, humans have sex primarily for pleasure.[10] This behavior in the above mentioned animals is also presumed to be for pleasure,[11] which in turn strengthens social bonds.
Sexual reproduction in eukaryotes is a process whereby organisms form offspring that combine genetic traits from both parents. Chromosomes are passed on from one generation to the next in this process. Each cell in the offspring has half the chromosomes of the mother and half of the father.[21] Genetic traits are contained within the deoxyribonucleic acid (DNA) of chromosomes—by combining one of each type of chromosomes from each parent, an organism is formed containing a doubled set of chromosomes. This double-chromosome stage is called "diploid", while the single-chromosome stage is "haploid". Diploid organisms can, in turn, form haploid cells (gametes) that randomly contain one of each of the chromosome pairs, via meiosis.[22] Meiosis also involves a stage of chromosomal crossover, in which regions of DNA are exchanged between matched types of chromosomes, to form a new pair of mixed chromosomes. Crossing over and fertilization (the recombining of single sets of chromosomes to make a new diploid) result in the new organism containing a different set of genetic traits from either parent.
Organisms of many species are specialized into male and female varieties, each known as a sex.[1][2] Sexual reproduction involves the combining and mixing of genetic traits: specialized cells known as gametes combine to form offspring that inherit traits from each parent. The gametes produced by an organism define its sex: males produce small gametes (e.g. spermatozoa, or sperm, in animals; pollen in seed plants) while females produce large gametes (ova, or egg cells). Individual organisms which produce both male and female gametes are termed hermaphroditic.[2] Gametes can be identical in form and function (known as isogamy), but, in many cases, an asymmetry has evolved such that two different types of gametes (heterogametes) exist (known as anisogamy).
A documentary is a documentary and a movie inspired by real events is just that. Each stand alone. RBG is an outstanding documentary to which On the Basis of Sex should not be compared. Yes, the movie is old fashioned reminding one of the classic movies of the 40s. So what. The subject matter is still timely even more so in the climate we are now living in...unfortunately there are probably many who want to go back to the "great" pre-Ginsburg days.
A Naval Criminal Investigation Service probe found Wallace allegedly assaulted the sailor in Pensacola while she was sleeping, causing some bodily harm. Wallace was in Pensacola during free time off-base. Prosecutors said he attempted to obstruct justice by asking a second lieutenant to lie to NCIS agents and deleting communications from another sailor’s cell phone.
A Naval Criminal Investigation Service probe found Wallace allegedly assaulted the sailor in Pensacola while she was sleeping, causing some bodily harm. Wallace was in Pensacola during free time off-base. Prosecutors said he attempted to obstruct justice by asking a second lieutenant to lie to NCIS agents and deleting communications from another sailor’s cell phone.

Either of two divisions, male and female, into which most sexually reproducing organisms are grouped. Sex is usually determined by anatomy, the makeup of the sex chromosomes, and the type and amount of hormones produced. When the sex of an organism is determined by the sex chromosomes, males and females are generally produced in equal numbers. In other organisms, such as bees and wasps, in which females develop from fertilized eggs and males develop from unfertilized eggs, distribution of the sexes is unequal.
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