Based on interviews and focus group discussions conducted in northern Laos, this study explores Akha understandings of customary first pre-pubertal sex acts, a thonh thong ('break through vagina' [BV]) for girls and yaha heu ('open foreskin' [OF]) for boys, which are thought to enable the maturing of bodies into adulthood. The study also examines the practice of a thor ta yang ('Welcome Guest') in which sexually initiated girls have sex with male visitors to Akha villages. The study found that many young women experience BV as painful and traumatic. However, since all Akha in the study 'knew' that young bodies will not mature into attractive, healthy adults if they do not perform BV and OF, attitudes were largely positive. Both men and women are at increasing risk of STIs, including HIV, since resettlement and an influx of non-Akha into the area. We conclude that Akha villagers should be included in the planning of future public health strategies that do not violate their cultural commitments and dignity but that help them resist potential exploitation and threats to their health. Such strategies might include sexual education programs and encouraging the delay of BV and OF.