question: What biological functions exactly drive sexual attraction in heterosexuals? How and why is it different for people of other orientations (if so)?
comment: Evolution is a guessing game whenever a genetic combination results in succesful reproduction it's like winning a free spin and big parts of that combination get to try again. Hormones and body chemistry create urges that coincidentally create opportunities to share genetic material. Very rarely that results in a succesful combination of genetic material but WAAAAY more often it doesn't. Men can be attracted to infertile women, pregnant women, post-menopausal women and pictures of women. All of those would have the same chance of producing fertile offspring as a man being attracted to another man. Genes dont plan, they gamble.
passages: Neuroscience and sexual orientation
  
  Sexual orientation is an enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex or gender, the same sex or gender, or to both sexes or more than one gender. The ultimate causes and mechanisms of sexual orientation development in humans remain unclear and many theories are speculative and controversial. However, advances in neuroscience explain and illustrate characteristics linked to sexual orientation. Studies have explored structural neural-correlates, functional and/or cognitive relationships, and developmental theories relating to sexual orientation in humans.
  
  Section::::Developmental neurobiology.
   Extensive research suggests that specific feelings, behaviours and cognitions are associated with the development of affiliative bonds and that these underlying processes responsible for sexual desire and affiliative bonds are functionally independent. Endogenous opioids, catecholamines, and neuropeptides (such as oxytocin and vasopressin) are responsible for the reward circuitry of the mammalian brain; through conditioned associations and reinforcement these neurochemicals regulate the biological processes that facilitate bonding.
  
  Section::::Evolutionary perspectives.
  
  Section::::Evolutionary perspectives.:Attraction.
   Human sexuality has many aspects. In biology, sexuality describes the reproductive mechanism and the basic biological drive that exists in all sexually reproducing species and can encompass sexual intercourse and sexual contact in all its forms. There are also emotional and physical aspects of sexuality. These relate to the bond between individuals, which may be expressed through profound feelings or emotions. Sociologically, it can cover the cultural, political, and legal aspects; philosophically, it can span the moral, ethical, theological, spiritual, and religious aspects.
   Discussions regarding the development of sexual identities as reinforced through environmental factors emphasize the impacts of socialization through media and other forms of educations. Early debates around the development of confident females and the promotion of healthy sexual desire suggested such interventions as “sexuality education” to foster the full development of the sexual self through education and more open discourse. Current emphasis on promoting positive associations with sexuality are not only being emphasized by means of exposure through the educational system and social media; researchers are promoting the importance of understanding the diverse needs of men and women at all stages of life, by means of various forms of research. Studies have shown that other ways of nurturing sexual desire throughout the aging process include valuing sexuality, maintaining the health of each partner, good sexual functioning, positive sexual self-esteem, and a sexually skillful partner.
   The ability of a person's physical and other qualities to create a sexual interest in others is the basis of their use in advertising, film, and other visual media, as well as in modeling and other occupations.
   Section::::Sexual preferences and hormones.:Ovulation and female sexual preferences.
  
  There is evidence that women's mate preferences differ across the ovarian cycle. A meta analysis, investigating 50 studies about whether women's mate preferences for good gene-related male traits changed across the ovarian cycle found that women's preferences change across their cycle: Women show the greatest preference for good gene male traits at their most fertile window.
   Which aspects of a person's sexuality attract another is influenced by cultural factors; it has varied over time as well as personal factors. Influencing factors may be determined more locally among sub-cultures, across sexual fields, or simply by the preferences of the individual. These preferences come about as a result of a complex variety of genetic, psychological, and cultural factors.
  
  A person's physical appearance has a critical impact on their sexual attractiveness. This involves the impact one's appearance has on the senses, especially in the beginning of a relationship:
   Section::::Influences on sexual desire.:Sex and gender influences.:Implications for same and other-sex attractions.
   Sexual desire has been described as a “longing for sexual union”, it associates with certain behaviours that are more linked to arousal and states of fear, concern and enhanced attention to others, and sexual cue displays such as lip biting and touching. In keeping with the correlation between sexual desire and arousal, sexual desire is mediated by gonadal estrogens and androgens.
   Section::::Biosocial theory.
  
  Kenrick and Trost (1987) have formulated a Biosocial theory of heterosexual relationships which encompasses several stages of seduction. This includes five stages of natural progression:
  
  BULLET::::1. Individuals identify a potential partner based on desired characteristics such as physical attraction
  
  BULLET::::2. Both individuals establish contact
  
  BULLET::::3. Other traits of the individual that are not necessarily explicit are analysed to determine fitness
  
  BULLET::::4. A physical relationship is established
  
  BULLET::::5. The relationship is either successful and progresses or discontinued
   Females at different stages of their menstrual cycle have been shown to display differences in sexual attraction. Heterosexual females not using birth control pills who are ovulating (high levels of estrogens) have a preference for the scent of males with low levels of fluctuating asymmetry. Ovulating heterosexual females also display preferences toward masculine faces and report greater sexual attraction to males other than their current partner. From an evolutionary perspective, increases in estrogens during fertile periods in females may direct sexual motivation toward males with preferential genes (the good genes hypothesis).
   Section::::Evolutionary perspectives.:Affectional bonding.
  
  Evolutionary theories suggest that reproductive mating is responsible for sexual desire while pair bonding underlies the mechanisms of romantic love. Specifically, attachment is suggested as extremely influential for the development of romantic love, which begins with infant-caregiver attachment and translates, in adulthood, to the development of romantic relationships.
   Many theories concerning the development of sexual orientation involve fetal neural development, with proposed models illustrating prenatal hormone exposure, maternal immunity, and developmental instability. Other proposed factors include genetic control of sexual orientation. No conclusive evidence has been shown that environmental or learned effects are responsible for the development of non-heterosexual orientation.
   While human sexuality is well understood, scientists do not completely grasp how other animals relate sexually. However, current research studies suggest that many animals, like humans, enjoy sexual relations that are not limited to reproduction. Dolphins and bonobos, for example, are both well known to use sex as a "social tool to strengthen and maintain bonds." Ethologists have long documented the exchanges of sex to promote group cohesion in social animals. Cementing social bondage is one of the most prominent theorized selective advantages of group selection theory. Experts in the evolution of sex such as John Maynard Smith advocate for the idea that the exchange of sexual favors helps congeal and localize the assortment of alleles in isolated population and therefore is potentially a very strong force in evolution. Maynard Smith has also written extensively on the "seminal fluid swapping theory" logistic application of the assortment of alleles as a more accurate synthetic depiction of the Hardy–Weinberg principle in cases of severely interbreeding populations.
   People consciously or subconsciously enhance their sexual attractiveness or sex appeal for a number of reasons. It may be to attract someone with whom they can form a deeper relationship, for companionship, procreation, or an intimate relationship, besides other possible purposes. It can be part of a courtship process. This can involve physical aspects or interactive processes whereby people find and attract potential partners, and maintain a relationship. These processes, which involve attracting a partner and maintaining sexual interest, can include flirting, which can be used to attract the sexual attention of another to encourage romance or sexual relations, and can involve body language, conversation, joking, or brief physical contact.
   The evolutionary theory of human interpersonal attraction states that opposite-sex attraction most often occurs when someone has physical features indicating that he or she is very fertile. Considering that one primary purpose of conjugal/romantic relationships is reproduction, it would follow that people invest in partners who appear very fertile, increasing the chance of their genes being passed down to the next generation. This theory has been criticized because it does not explain relationships between same-sex couples or couples who do not want children, although this may have something to do with the fact that whether one wants children or not one is still subject to the evolutionary forces which produce them.
   The early fixation hypothesis includes research into prenatal development and the environmental factors that control masculinization of the brain. Some studies have seen pre-natal hormone exposures as the primary factor involved in determining sexual orientation. This hypothesis is supported by both the observed differences in brain structure and cognitive processing between homosexual and heterosexual men. One explanation for these differences is the idea that differential exposure to hormone levels in the womb during fetal development may change the masculinization of the brain in homosexual men. The concentrations of these chemicals is thought to be influenced by fetal and maternal immune systems, maternal consumption of certain drugs, maternal stress, and direct injection. This hypothesis is connected to the well-measured effect of fraternal birth order on sexual orientation.
   Section::::Biological theories of cause of sexual orientation.:Exotic becomes erotic.
   Through a series of studies, Richard Lippa has investigated the ways in which high levels of sex drive influence sexual attraction either as a generalized energizer of overall attraction to both sexes, or as an energizer of dominant sexual attraction to either men or women, dependent on sexual orientation. Results reveal that for heterosexual and gay men, as well as lesbian women, there is a strong polarization between high sex drive and self-reported same and other-sex attraction. However, this association was not present for all lesbian women or heterosexual women, who showed a general pattern of high sex drive associated with increased attraction to both men and women.
   Along with bisexuality and homosexuality, heterosexuality is one of the three main categories of sexual orientation within the heterosexual–homosexual continuum. Across cultures, most people are heterosexual. Scientists do not know the exact cause of sexual orientation, but they theorize that it is caused by a complex interplay of genetic, hormonal, and environmental influences, and do not view it as a choice. Although no single theory on the cause of sexual orientation has yet gained widespread support, scientists favor biologically-based theories. There is considerably more evidence supporting nonsocial, biological causes of sexual orientation than social ones, especially for males.
   Women have been found to report greater sexual attraction to men other than their own partners when near ovulation compared with the luteal phase. Women whose partners have high developmental stability have greater attraction to men other than their partners when fertile. This can be interpreted as women possessing an adaptation to be attracted to men possessing markers of genetic fitness, therefore sexual attraction depends on the qualities of her partner.
  
  Section::::Sexual preferences and hormones.:Ovulation and ornamentation.
   Certain characteristics may be innate in humans; these characteristics may be modified by the physical and social environment in which people interact. Human sexuality is driven by genetics and mental activity. The sexual drive affects the development of personal identity and social activities. An individual's normative, social, cultural, educational, and environmental characteristics moderate the sexual drive. Historically, two schools in psychology took opposing positions in the nature-versus-nurture debate: the Psychoanalytic school led by Sigmund Freud and the Behaviorist school which traces its origins to John Locke.
   It is believed by many that sexual desire plays an important role in romantic love and that it may be an extremely important factor in strengthening the interpersonal dynamic of romantic relationships; recent studies have supported these theories and have also provided further insight into the various neurobiological substrates that influence the development of various types of relationships.
  
  Section::::Sexual desire and love.:Different types of love.
   Section::::Predictors for long-term relationship success.
  
  In a study conducted by Shackleford, Schmitt, & Buss (2005), four dimensions were found that seem to predict how compatible two people are in what they're looking for in a long-term relationship. The survey was given to over 9,800 people from 37 different cultures across 6 continents and 5 islands. The four dimensions are:
  
  BULLET::::- Love vs. Status/Resources—trade-off between a loving relationship and a partner with adequate resources and status
  
  BULLET::::- Dependable/Stable vs. Good Looks/Health—trade-off between choosing an emotionally stable partner and one that is physically attractive
   Section::::Biological theories of cause of sexual orientation.
  
  Section::::Biological theories of cause of sexual orientation.:Early fixation hypothesis.
  
presuppositions: Sex drive is different in heterosexuals and other orientations. Biological functions that drive sexual attraction in heterosexuals is different for people of other orientations.
corrections: Sex drive is genes gambling. Sometimes it works, sometimes not.  Biological functions that drive sexual attraction in heterosexuals isn't necessarily different for people of other orientations.
raw_presuppositions: Sex drive is different in heterosexuals and other orientations. Biological functions that drive sexual attraction in heterosexuals is different for people of other orientations.
raw_corrections: Sex drive is genes gambling. Sometimes it works, sometimes not.  Biological functions that drive sexual attraction in heterosexuals isn't necessarily different for people of other orientations.