The sexual and reproductive health literature abounds with research detailing results of national surveys, findings of large-scale surveillance efforts, evaluations of initiatives aimed at achieving this or that public health goal, and descriptions of the behaviors and needs of groups widely known to be at high risk of poor outcomes. All of this is, of course, vital to programmatic and policy initiatives. But at the same time, it obscures issues of health and rights for populations that get relatively little attention from researchers, practitioners and policymakers. In this special issue of Perspectives on Sexual and Reproductive Health, we are pleased to highlight the circumstances of a number of understudied populations.

• In Hawaii, which has one of the highest unintended pregnancy rates in the country, Native Hawaiians are more likely than any other ethnic group to have unintended pregnancies. To explore the context in which Native Hawaiians make pregnancy-related decisions and how pregnancy is viewed in this population, Reni Soon and colleagues conducted semistructured interviews with diverse key informants from within the community (see article). They found that in many respects, Native Hawaiian cultural values regarding family and childbearing trump individual priorities. "The most striking finding," they write, "is that an unintended pregnancy means something different to the Native Hawaiian community than it does to the public health and medical communities, and possibly than it does to other communities in Hawaii." An understanding of -Native Hawaiians’ distinctive perspectives on pregnancy and pregnancy planning, the authors conclude, is crucial to the success of any family planning efforts in this population.

• As the prevalence of autism has grown, so has the need for sex education for individuals on the autism spectrum; yet, firsthand information about their sexual experiences is scarce. To help fill this gap, −Jessica Penwell Barnett and Eleanor Maticka-Tyndale conducted in-depth, Internet--facilitated interviews with 24 adults recruited through websites and Listservs serving the autistic community (see article). Given autistic individuals’ difficulties with social communication and sensory processing, it is perhaps not surprising that participants’ most frequent sexual concerns pertained to problems with courtship and with sensory regulation in the context of sexual behavior. Participants expressed their dissatisfaction with what little sex education they had received, and many of the inadequacies they discussed highlight the unique needs of this population: In one participant's words, "Autistic people should be given more specifics." The authors argue that disability-relevant sex education is an ongoing need for autistic individuals throughout the life course.

• Men who have sex with men account for a vast proportion of U.S. syphilis cases, and after a first infection, many are reinfected within a fairly short time. Aaron Plant and his team explored possible reasons for this by conducting in-depth interviews with Los Angeles men who reported having male sex partners and having had multiple -syphilis -diagnoses within the previous five years (see article). Interviewees -generally -recognized that their sexual behavior made them vulnerable to infection, but considered this vulnerability an acceptable part of being sexually active. Indeed, while most said that they changed their behavior for a short time after receiving a diagnosis in order to prevent transmitting the infection, few were open to making long-term changes. Participants’ unwillingness to adopt safer sexual practices, the authors observe, suggests that interventions aimed at reducing risky behaviors "are unlikely to succeed" in this population; further work is needed to identify more promising strategies.

• Youth who have had episodes of maltreatment that have been reported to child protective services are known to be more likely than others to engage in risky sexual behavior and to experience teenage pregnancy. New research by Julie A. Cederbaum and colleagues demonstrates that they are at risk of other adverse sexual health outcomes as well (see article). In a population-based study of adolescent first-time mothers in California, Cederbaum et al. found that those with a history of involvement with child protective services were more likely than others to have an STD at the time they gave birth and to have previously had an abortion. As the authors write, the findings suggest the need for further work exploring the mechanisms underlying these associations, how those mechanisms affect sexual health outcomes and whether adolescents who have been involved with child protective services require targeted sexual health interventions.

• Homeless youth have a considerably higher risk of acquiring HIV than their peers who are stably housed, and a focus group study by Diane Santa Maria and coinvestigators provides preliminary explanations for the disparity (see article). Three themes emerged from the researchers’ discussions with a sample of homeless 14–24-year-olds: These young people frequently engaged in risky sexual practices, sometimes as a means of coping with stress; they often exchanged sex for money or other necessities; and many had been victimized as children or since becoming homeless. Furthermore, participants described feelings of stigma, shame, self-reliance and mistrust of others, all of which could prevent them from obtaining a range of necessary services. The researchers note that HIV prevention efforts for homeless youth have had limited effect to date; their findings, they believe, support the need for such efforts to take into account the context of youth homelessness.

• Women who spend time in jail or prison often come from, and return to, situations marked by numerous disadvantages, including inadequate access to sexual and reproductive health services. Three articles in this issue address the needs of this understudied population.

Carolyn Sufrin and her research team report on a program in the San Francisco County Jail that provided long-acting reversible -contraceptive methods—IUDs and implants—to those who chose them during the optional women's health exam offered soon after a woman enters the facility (see article). Using electronic medical record systems of both the jail and community-based clinics where women obtained services after their release, the researchers tracked a number of outcomes. They found no complications from IUD insertion and no serious ones following insertion of implants; the median duration of known use was about 11 months for the IUD and 13 months for the implant. The reason women most commonly gave for discontinuing their chosen method was a desire to get pregnant. These results, Sufrin et al. conclude, demonstrate that it is safe and feasible to provide IUDs and implants to incarcerated women.

In one of two comment articles, Sufrin and a different group of coauthors cast incarcerated women's sexual and reproductive health needs as a matter of reproductive justice (see article). They report that because relevant policies are often unclear or nonexistent, incarcerated women may receive substandard prenatal care, be prevented from having abortions, be pressured into using contraceptives (or particular methods), or be shackled during pregnancy or labor. Noting that disadvantage "[characterizes] the lives of many women enmeshed in the criminal justice system," the authors argue that providers and -advocates "must work not only to improve access to reproductive health services for women while they are incarcerated, but also to promote policy changes that invest in women's lives outside of prison or jail."

Bethany Kotlar and colleagues take a close look at the role correctional facilities can—and sometimes do—play in promoting good maternal and infant health (see article). In their comment, they describe facility-based programs that have included doula support for labor and delivery; peer education for pregnant women and new mothers; family planning counseling; instruction in newborn and toddler parenting skills; and on-site nurseries, which enable mothers and infants to create the strong bonds that are essential in the first months after birth. The authors note that programs such as these have documented successes but are not sufficiently widespread. Increased investment in such initiatives, they conclude, "will allow…correctional facilities to lower costs and recidivism, and incarcerated mothers and their families to have the chance to thrive."

• Finally, the Digests section contains reports on HIV testing among transgender individuals, sexual behavior among American Indian youth, contraceptive use among cancer survivors and more.

—The Editors