Like all adults, adults with intellectual disabilities (ID, formerly mental retardation) have normal sexual interests and desires. These desires motivate them to be attracted to sexual partners and to engage in sexual activities. Of course, a common consequence of sexual activity is pregnancy. Historically, society attempted to restrict the reproductive rights of adults with ID. These reasons were born of ignorance. They bordered between delusional and parental in nature.
At the beginning of the 20th century, adults with ID were subjected to the philosophy of eugenics. Eugenics proposed that some people's genetic backgrounds were inferior to others. From this notion flowed the goal of improving the human gene pool. This goal was to be achieved by extermination or sterilization of so-called inferiors. The most horrifying application of eugenics was Hitler's attempts to exterminate people of Jewish decent. Unfortunately, people with ID were also exposed to eugenics. Individuals with intellectual disabilities were assumed to have an inferior, defective genetic pool. Therefore, they were considered a reproductive threat to the integrity of the human gene pool.
Two branches of eugenics were influential. Proponents of positive eugenics urged elite families to reproduce in quantity. The idea was to drown out the reproductive efforts of 'undesirables.' These undesirables included 'promiscuous' women; persons of color; and people with intellectual disabilities (to name but a few). Proponents of negative eugenics took the idea of genetic purity a step further. They believed a more permanent solution was to prevent 'undesirables' from reproducing. This meant sterilizing them against their will.
During the early part of the 20th century, most people with ID were institutionalized. These institutions often sterilized their patients. Birth control was very limited at that time. These institutions were not designed to handle pregnancies and infants. At first, laws governing forced sterilization differed from state to state. However, a groundbreaking Supreme Court case, Skinner V. Oklahoma (1942) found that involuntary sterilization infringed on an individual's inalienable right to procreate. Despite the court's ruling, some states and facilities continued the practice of sterilization.
The policy regarding reproductive rights of people with IDs is still debated. On the one hand, persons with ID have the same rights as any other citizen. This includes the right to marry and to have children. They also have the right to use contraception to prevent pregnancy and sexually transmitted disease. Since people with IDs are transitioning into mainstream society, it's sensible to expect they share the same rights of that society.
The other side of the reproductive debate centers the defining characteristics of ID. These are limited mental abilities and difficulty with life skills. Can people with limited mental abilities fully understand the ramifications of sexual activity? The answer is, it depends. People with severe intellectual disabilities may not. For instance, some women with ID may not fully comprehend what is happening to their bodies during pregnancy. Likewise, some people with ID struggle with self-care. Therefore, it is reasonable to expect they may have difficulty caring for a child. Opponents would argue many people without ID have the same difficulties caring for children well. Why single out people with ID?
These debates will continue. Hopefully, the above discussion makes clear that no two people with ID are the same. It is obvious that some fully understand their sexuality. Some are fully capable of being good and loving parents with sufficient supports.
The American Association on Intellectual and Developmental Disabilities has published a position paper on sexuality. It includes a discussion of reproductive rights.