Sexuality in a community based sample of adults with autism spectrum disorder

Abstract

Few studies have examined the sexual attitudes and behaviours of individuals with high functioning autism spectrum disorders (ASDs) living in community settings. A total of 82 (55 female and 17 male) adults with autism were contrasted with 282 members of the general population on their responses to an online survey of sexual knowledge and experiences. Findings revealed that individuals with ASD display an interest in sex and engage in sexual behaviours and showed no significant differences in breadth and strength of sexual behaviours and comprehension of sexual language when contrasted with non-ASD participants. However, despite these similarities, a higher rate of asexuality was found among individuals with ASD. In addition, the results of the current study indicated that females with ASD show a significantly lower degree of heterosexuality when compared to males with ASD. The results also suggested a higher degree of homosexuality among females with ASD although this effect did not reach significance.

Introduction

Autism spectrum disorders (ASDs) are a group of developmental disorders characterized by impairments in social interaction, verbal and non-verbal communication, and stereotyped and repetitive behaviours (American Psychiatric Association, 2000, pp. 69–70). Past research has rarely examined the sexual interests and behaviours exhibited by this population. Yet, research on this topic is of particular importance due to the fact that while individuals with ASDs demonstrate sexual behaviours and interests, these behaviours are often displayed inappropriately (Hellemans, Colson, Verbraeken, Vermeiren, & Deboutte, 2007). There is also some evidence indicating that sexuality among individuals with ASDs differs from that in the general population at a fundamental level. For example, an increase in sexual behaviours towards the same sex has been described (Haracopos & Pedersen, 2004). Differences in sexual attitudes were also apparent in individuals with ASD when compared to the general population and those with other disabilities. Higher levels of negative attitudes with respect to homosexual behaviour and masturbation have been reported among individuals with ASD compared to the general population (Konstantareas & Lunsky, 1997). However, the level of endorsement of these activities was higher among those with ASD than among individuals with other developmental disabilities. Konstantareas and Lunsky suggested that negative attitudes might have been imposed on ASD participants by caregivers.

Some studies have found a lack of person-oriented sexual behaviours among individuals with autism spectrum disorders. A study of 89 adults living in group homes in North Carolina (Van Bourgondien, Reichle, & Palmer, 1997) showed that person-oriented sexual behaviour was exhibited by only 34% of the participants, although masturbation was common. A high degree of asexuality among individuals with ASD was also found in a community based sample of individuals with ASD (Marriage, Wolverton, & Marriage, 2009). Approximately 33% of Marriage et al.’s sample appeared to be asexual. A comparable figure for asexuality in the general population is suggested to be 1% (Bogaert, 2004). Of the ASD participants who displayed an interest in sexual behaviour, most had significant difficulties in this domain. Some attempted relationships that failed and two of the males in the study temporarily sought gender reassignment (Marriage et al.).

Much of past research on sexuality and ASDs has focused on persons living in group home settings. Haracopos and Pedersen (2004) conducted a nationwide study of the sexuality of individuals with autism living in group homes across Denmark. Of the 81 adults in the study, 74% displayed person-oriented sexual behaviours. Level of functioning seemed to be a determining factor in sexual orientation among participants. Among the highest functioning individuals, 75% directed their sexual behaviours exclusively towards the opposite sex. This was true of only 27% of the fair functioning individuals, and none of those who were low functioning. Of the 34 individuals who showed definite signs of sexual behaviour, 41% displayed exclusively heterosexual interactions, 35% directed behaviours towards both sexes, 9% showed exclusive homosexual interactions, and researchers were unable to determine the sexual preferences of the remaining 15% (Haracopos & Pedersen, 2004). Another study of 24 male adolescents with high functioning autism who lived in institutional settings showed that 58% of the patients had a clear heterosexual orientation, 13% had a clear bisexual orientation, 4% had a clear homosexual orientation, and the sexual orientation of the remaining 25% was unclear (Hellemans et al., 2007). By comparison, an international study on homosexuality in the general population (Sell, Wells, & Wypij, 1995) reported that the incidence of males in the general population engaging in homosexual activity within the last five years was between 4.5 and 10.7% for the United States, the United Kingdom, and France. Comparable figures for females were between 2.1 and 3.3%. The levels of homosexual attraction were considerably higher at between 16.3 and 20.8% for males and between 17.8 and 18.6% for females (Sell et al.).

The link between ASD and increased homosexuality might arise from the fact that both the development of autistic traits and homosexuality are related to prenatal androgen exposure. Prenatal androgens are believed to masculinize the brain and exposure to extremely high levels of androgens in utero may contribute to both homosexuality and ASD (Auyeung et al., 2009, Baron-Cohen, 2002). Persons exposed to high levels of prenatal androgens have lower 2D:4D digit ratios than expected, with females showing patterns more typical of males (Lutchmaya, Baron-Cohen, Raggatt, & Manning, 2004). Individuals who score high on autistic traits also exhibit digit ratio patterns indicative of prenatal androgen exposure (Manning, Baron-Cohen, Wheelwright, & Sanders, 2001). Furthermore, Kraemer et al. (2006) found a relationship between low digit ratios and homosexuality in females but not in males, suggesting that prenatal androgen exposure is related to female homosexuality.

At present, research on sexual orientation and ASD outside of group home settings is lacking. Studies involving individuals with ASD living in group homes may be difficult to generalize to those living independently in the community. Several factors contribute to this lack of generalizability. Individuals living in group homes are typically lower functioning than those who are capable of independent living. Furthermore, group homes often house members of only one sex and there are few opportunities for social interactions with the opposite sex or individuals without disabilities. This might affect the sexual behaviour patterns of those housed in group homes. Since the incidence of homosexuality among those with ASD may be different among males and females, it is also of importance to state that none of the previous studies on autism and sexual orientation compared the participants by gender.

The present study utilized an online survey aimed at comparing the sexual knowledge and experiences of individuals with high-functioning ASD living in the community to that of members of the general population. We predicted that individuals with ASD would score lower on measures of both sexual knowledge and experience than those without ASD. This study also aimed to determine whether there was a relationship between high-functioning autism and homosexuality in a community based sample of participants. The prenatal androgen theory suggests that there would be a higher incidence of same-sex oriented behaviours and attitudes and a correspondingly lower incidence of behaviours and attitudes targeting members of the opposite sex among females with ASD. The reverse finding, i.e. a lower rate of homosexuality and higher rate of heterosexuality would be expected among males. The lower rate of homosexuality among males is expected because a hypermasculinized brain would likely result in increased gynephilia.