It's the first cite I found, but if that's not religion-neutral enough for you, I can find plenty more.
Sex causes the release of hormones such as oxytocin. Most people aren't capable, especially when young, of having sex with someone, never seeing that person again, and being okay with the experience.
"Even when romantic love is not linked with reproduction, this passion can provide a teen or young adult with some exceptional personal and social benefits, including exhilarating joy, increased energy and optimism, feelings of intimacy, self-esteem, inclusion in health-giving social groups, exercise, social and personal support, and crucial practice in the skills of building a long-term partnership—skills they will need to make the most important social contract of their reproductive lives."
"Even when romantic love is not linked with reproduction, this passion can provide a teen or young adult with some exceptional personal and social benefits, including exhilarating joy, increased energy and optimism, feelings of intimacy, self-esteem, inclusion in health-giving social groups, exercise, social and personal support, and crucial practice in the skills of building a long-term partnership—skills they will need to make the most important social contract of their reproductive lives." (Emphasis mine.)
You missed that inconvenient detail, didn't you? Romantic love and casual sex are mutually exclusive. (I'm railing against casual sex, not all premarital sex; if the latter, I'd be a hypocrite.)
Women may be particularly vulnerable to falling in love with a casual sex partner because seminal fluid also contains dopamine and tyrosine, a building block of dopamine (Burch & Gallup, in press). Although these chemicals do not pass across the blood-brain barrier, elevated activities of dopamine and tyrosine may affect brain physiology through other complex interactions. In fact, people report that sex can lead to romantic love. The natives of rural Nepal even use an off-color term for this phenomenon, saying "Naso pasyo, maya basyo," or "the
penis entered and love arrived" (Ahearn, 1998).
Once again, this biological link between lust and romantic love is not direct or simple. Athletes who inject synthetic androgens to build muscle do not fall in love. When middle-aged men and women inject androgens or apply testosterone cream to stimulate their sex drive, their sexual thoughts and fantasies increase (Sherwin & Gelfand, 1987; Sherwin, Gelfand, & Brender, 1985). But neither do these individuals become enamored.
Nevertheless, the chemical interactions between testosterone and dopamine and the chemical changes that accompany sexual arousal suggest that those who engage in sexual intercourse are more likely to fall in love; their threshold for this passion is lowered. And women who engage in sex without a condom may be even more susceptible to romantic passion. Hence teens and young adults who pursue
"casual sex" with a friend or stranger can become enamored with their sexual partner even when they have no intention of beginning a romance.
Lust Can Trigger Attachment
Sexual activity can also trigger the brain system for attachment. In humans, orgasm elevates the activity of oxytocin and vasopressin (Carmichael et al., 1987; Young
et al., 1998); and these neuropeptides are associated with attachment in people and other animals (Wang, Ferris, & DeVries, 1994; Williams et al., 1994" Young et al., 1998). ' B Hence, teenagers who engage in casual sex can trigger the brain system for attachment (as well as that for romantic love), leading to complex, unanticipated emotional entanglements with psychologically and socially unsuitable mating partners." (Emphasis mine.)
In other words, casual sex hacks the brain system, by aping at least some of the biochemical signature of romantic love. Of course, in most cases, it's not romantic love but a shallow infatuated attachment. In any case, it's not good for you.
"Romantic love and casual sex are mutually exclusive."
You speak for yourself and no-one else. Most women would consider being boned by James Bond for one night only to be a highly romantic proposition.
I'm not James Bond but I do my best. I've never had any complaints. At least I have some experience in such things. You are just making shit up to support your wacky beliefs.
Is there any evidence of this not coming from religious propaganda?