Adolescent Sexual Development PDF

Chapter 2: Adolescent Sexual Development Learning Objectives: Sexual Development 1. Define and describe puberty 2. Describe the consequences of early and late puberty 3. Describe disorders of sexual development 4. Name and define aspects of sexuality 5. Discuss p...

Chapter 2: Adolescent Sexual Development Learning Objectives: Sexual Development 1. Define and describe puberty 2. Describe the consequences of early and late puberty 3. Describe disorders of sexual development 4. Name and define aspects of sexuality 5. Discuss patterns of sexual behavior 6. Define sexual orientation and describe its developmental time course 7. Describe sociosexual orientation 8. Define erotophilia Puberty Primary sex characteristics are present at birth and include the external genitalia and internal sex organs. Puberty is the time in life when individuals become sexually mature and develop secondary sex characteristics or the physical features of adult men and women that result from adult levels of sex steroid hormones. Sex steroid hormones have organizational effects that permanently determine the anatomy of cells, tissues, and organs. While most organizational effects occur prenatally and early in development, some occur during puberty. Sex steroid hormones also produce transient changes in physiology and Figure 0-1. The hypothalamic pituitary gonadal axis. behavior, these are activational effects. The hypothalamus is the part of the brain that regulates the gonads through gonadotropin releasing hormone GnRH which stimulates the pituitary to release gonadotropins (follicle stimulating hormone (FSH) and luteinizing hormone (LH)) (Figure 1). Gonadotropins stimulate the ovaries and testis to produce sex steroids. Although blood levels of testosterone are higher in males and estrogen and progesterone are higher in females, the three hormones are found in (and important for) both sexes. What Triggers Puberty? The cells of the hypothalamus that produce gonadotropin are regulated by other cells in the hypothalamus that produce a peptide neurotransmitter called kisspeptin. This neurotransmitter stimulates gonadotropin secretion. Kisspeptin producing cells are different in males and females and so the control of gonadotropin secretion is sexually dimorphic. The timing of puberty is primarily genetic in both sexes but is also influenced by the amount of body fat an individual has. This effect is present in both males and females but is stronger in females. The leptin producing cells of the hypothalamus have receptors for leptin a hormone produced by fat cells. Leptin stimulates kisspeptin secretion and results in higher gonadotropin levels. Higher body fat contributes to early puberty especially in girls. Better nutrition has caused the average age of menarche or first period to drop from 16 to 11 years since the mid-1800s. Psychosocial stress may also be associated with early puberty in girls (Breehl & Caban, 2022; Dunger et al., 2006). The stages of puberty assessed by pediatric clinicians are called Tanner stages (Figure 2) (Breehl & Caban, 2022). Figure 0-2. Tanner stages of pubertal development in girls (Table 1) and boys (Table 2) (Breehl & Caban, 2022). 2 The first sign of puberty in girls is thelarche or breast development. Menarche is the first menstrual period which occurs 1.5 to 3 years later. Growth in height stops shortly after menarche. For boys the first sign of puberty is testicular enlargement. First ejaculation occurs about 1 year after the testis begin to grow but sperm are not produced for another year after that (Breehl & Caban, 2022). Early and Late Puberty Early puberty, also called precocious puberty is the early development of secondary sex characteristics. Early means before the age of eight in girls or before the age of nine in boys. Delayed puberty is the lack of physical evidence of puberty by 2 to 2.5 standard deviations above the mean age for the initiation of puberty. That is 13 for girls and 14 for boys for the first sign of puberty. Early and late puberty should be evaluated by a pediatrician; however, the most common cause is “idiopathic” or unknown. Early puberty is linked to adverse physical and mental health outcomes. As previously discussed, adolescents’ decision making resembles that of patients that have damage to the ventromedial prefrontal cortex. Problems with decision making are expected to be worse in individuals who begin puberty early because the frontal lobes of the brain are underdeveloped. Longitudinal studies show that early puberty puts both girls and boys at risk for adverse health outcomes while late maturation is protective. For girls early menarche is associated with increased risk for depression, being overweight and more sex partners. For boys early maturation is associated with antisocial behavior, more sex partners, more drug use, less sleep and being overweight (Hoyt et al., 2020). Disorders of Sexual Development Disorders of sexual development include chromosomal disorders, and mutations in genes for hormonal synthesis and hormone receptors. Klinefelter’s syndrome (XXY karyotype) affects.1-.25% of those assigned male at birth and is a common cause of infertility, although pubertal development is normal (Klinefelter Syndrome, n.d.) (see https://livingwithxxy.org). Turner’s syndrome (X0 karyotype) also causes infertility and affects.25% of those assigned female at birth (Pasquino et al., 1997) (see https://turnersyndromefoundation.org). Congenital adrenal hyperplasia (CAH) is caused by mutations in genes for enzymes involved in steroid biosynthesis (Congenital Adrenal Hyperplasia, n.d.). CAH can cause masculinization of female genitalia and early puberty. Affected individuals have higher levels of androgens and may also have low cortisol (for one woman’s story see https://www.youtube.com/watch?v=gv6lVfJ_lPQ). Some individuals with an XY karyotype are assigned female at birth because they are phenotypic females with androgen insensitivity syndrome (AIS) (for one woman’s story see https://youtu.be/yuXL-3eoB-o). The gonads of people with AIS are in the pelvis and do secret testosterone and other gonadal steroids. Due to high risk of malignancy removal of the gonads is recommended. Because the body cannot respond to testosterone, affected people have female primary and secondary sex characteristics. Some people with AIS are partially insensitive to androgens and so they have female 3 genitalia and some male secondary sex characteristics including increased muscle mass. Caster Semenya, a South African runner and former Olympic gold medalist is a person with AIS who has been banned from athletic competition by the International Association for Athletics Federation (IAAF) (see a medical article about AIS and athletics https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7259991/). See Castor Semenya tell her story here https://youtu.be/mLtmeRnjoyA). Development of Sexual Behavior During Adolescence Term Definition Gender Identity Gender identity refers to the extent to which a person experiences oneself to be like others of one gender. A person’s sense of being male or female impacts how they view themselves and provides an important basis for their interactions with others. ―Transgender Transgender is an umbrella term for people whose gender identity or gender expression does not conform to that typically associated with the sex to which they were assigned at birth. Some who do not identify as either male or female prefer the term “gender nonbinary” or “genderqueer.” Sexual Orientation Sexual orientation refers to an enduring pattern of emotional, romantic and/or sexual attractions to men, women or both sexes. Sexual orientation also refers to a person's sense of identity based on those attractions, related behaviors and membership in a community of others who share those attractions. ―Heteronormativity The assumption that heterosexuality is the standard for defining normal sexual behavior and that male–female differences and gender roles are the natural and immutable essentials in normal human relations. According to some social theorists, this assumption is fundamentally embedded in, and legitimizes, social and legal institutions that devalue, marginalize, and discriminate against people who deviate from its normative principle (e.g., gay men, lesbians, bisexuals, transgendered persons). Sociosexual Orientation A dimension of personality that describes people’s comfort with and preference for sexual activity in the absence of love or commitment. People who are said to have an unrestricted sociosexual orientation (usually but not exclusively men) report more sexual activity outside of committed intimate relationships (e.g., one-night stands, short-term relationships, extramarital affairs). Erotophilia-Erotophobia A disposition to respond to sexual cues in a positive or negative way. Table 0-1. Terms describing aspects of sexual behavior. Adapted from the American Psychological Association Website and (Fisher et al., 1988). 4 Aspects of sexual behavior tend to be enduring, biologically based aspects of a person. Those named and defined in Table 1 include gender identity, sexual orientation, sociosexual orientation and erotophilia. For most individuals, gender identity aligns with their sex assigned at birth and this identity is recognized by early childhood. Throughout childhood individuals spend most of their time with peers of the same gender. For a small number of children, gender identity does not correspond to their sex assigned at birth and they can be diagnosed with gender dysphoria (Wiepjes et al., 2018). Puberty may be especially distressing to these individuals and medical suppression of puberty is part of helping them achieve good adjustment. Gender dysphoria does not persist into adolescence for most affected children (85%) (Steensma et al., 2013). Gender dysphoria can also start after adolescence or into adulthood (Steensma et al., 2013). Early adolescence appears to be an important time for gender identity development. During this time, physical puberty, being more explicitly treated as one's natal sex, and the discovery of sexuality are important life events (Steensma et al., 2013). Psychologists recognize that gender identity is on a continuum and is non-binary, in addition to male and female, other identities include “shemale,” “third gender,” “pan- /poly-/or omnigendered,” and “gender fluid” (Steensma et al., 2013) (see https://youtu.be/u5BAlzHtwqw). Sexual Activity Adolescents explore and begin to develop their sexual orientation. Cohort differences in sexual activity indicate that sexual activity started earlier for those born after 1960 and has remained stable. Irrespective of sex assigned at birth, in more recent birth cohorts, 12-13% report sexual intercourse by age 14; the median age at first sexual activity is 16.5 years. For those assigned female at birth the percentage reporting same sex behavior increased from 5.2% in the early Baby Boomer Cohort to about 9% in more recent cohorts. For those assigned male at birth same sex activity has remained stable over multiple cohorts at 3.8-6.1% in one study (Liu et al., 2015) and has increased from 4.5-8.2% in another study (Twenge et al., 2016). Age at first same sex sexual behavior has decreased from 28 years in the Baby Boomer cohort to 16 years in recent cohorts for those assigned female at birth; and from 19 years (Baby Boomer) to 16 years in recent cohorts for those assigned male at birth (Heron et al., 2015). Overall studies indicate that the median age for all sexual activity is currently about 16 years. Earlier sexual activity is associated with externalizing disorders irrespective of sex assigned at birth (Skinner et al., 2015). Half of all sexually transmitted infections occur in adolescence and emerging adulthood. These include chlamydia, gonorrhea, genital herpes, human papillomavirus (HPV), syphilis, and HIV (Adolescents and STDs | Sexually Transmitted Diseases | CDC, 2022). 5 Sexual Orientation Helping professionals aspire to assist all individuals in improving their wellbeing. Working with all people means respecting and accepting what individuals report regarding their sexual orientation. The American Psychological Association’s position is that sexual orientation is an “enduring” pattern (Table 1). But just how enduring is sexual orientation during adolescence? Whereas actual sexual behavior is observed or reported as described above, sexual orientation is a construct that must be defined so that it can be measured. How this construct is defined may impact how enduring it is measured to be. There are four commonly used measures of sexual orientation (1) Kinsey, 2) Shively, 3) Klein Sexual Orientation Grid and 4) Sell: Subscales Attraction, Contact, Identity) (Sell, 1997). Each defines sexual orientation in a different way that might not apply well to individuals under 18. There is general agreement that sexual orientation includes aspects of attraction, romantic feelings, sexual behavior and identity and these may not always agree (Friedman et al., 2004). The following data comes from a large (N>12k), recent epidemiologic study (Savin- Williams & Ream, 2007). Regarding attraction, up to 23% of 16–17-year-old males and 17% of 16-17 -year-old females report no sexual attraction. By early adulthood less than 4% of both sexes report no sexual attraction. Of 16 y/o males who report sexual attraction, 92% report exclusively heterosexual, 0.9% report exclusively homosexual attraction and 7% report attraction to both sexes. Of 16 y/o females who report sexual attraction, 94% report exclusively heterosexual, 1.5% report exclusively homosexual attraction and 4% report attraction to both sexes. In young adulthood exclusive heterosexual attraction is reported by 94% of males and 87% of females; exclusive homosexual attraction by 1% of males and 0.6% of females; and bisexual attraction by 4.6% of males and 12.4% of females. Opposite sex attraction is more stable (78% for males, 83% for females) between 16 and 24 years of age than any same sex attraction (about 50% stability for males and females). Note that change in reported attraction status is common in either direction (same to opposite and opposite to same). With respect to behavior, heterosexual behavior is 98% stable in males and 96.5% stable in females. Exclusively homosexual behavior is 71.6% stable in males and 76.8% stable in females. Bisexual behavior is 87-89% stable. How can helping professionals use statistics about adolescent sexual attraction, behavior, and identity? Research results may be summarized as follows: 1) same sex attraction is common in both sexes (♀, ♂); 2) Individuals whose sexual behavior is exclusively heterosexual may still change during and after adolescence; 3) likewise, individuals whose sexual behavior is exclusively homosexual may switch to bi- or heterosexual behavior. Sexual behavior is largely but not entirely stable. Given that many individuals begin sexual relations at 16 or later, sexual orientation identity and “coming out” are discussed when we cover emerging adulthood. 6 Sociosexual Orientation and Erotophilia In addition to gender identity and sexual orientation, sociosexual orientation describes an individual’s sexuality. Sociosexual orientation refers to a person’s attitudes, desires and behavior regarding sex outside of committed relationships; it is measured along a continuum from unwilling/restricted to willing/unrestricted (Gangestad & Simpson, 2000). Erotophilia is another characteristic of an individual’s sexuality and is the extent to which an individual finds sexuality enjoyable. Sociosexual orientation and erotophilia are correlated but appear to be separate aspects of sexuality. Although more studies are needed, sociosexual orientation and erotophilia have been measured in mid adolescence. Unrestricted sociosexuality and erotophilia are higher on average in teen boys than in teen girls. Erotophilia increases over the teen years for boys. Strong attachment to the same sex parent predicts a more restricted sociosexual orientation in teens (Mallet & Kindelberger, 2018). About 25% of 17-19 year old teens have not had sexual experiences. References Adolescents and STDs | Sexually Transmitted Diseases | CDC. (2022, June 30). https://www.cdc.gov/std/life-stages-populations/stdfact-teens.htm Breehl, L., & Caban, O. (2022). Physiology, Puberty. In StatPearls. 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