We report here on our findings from adolescent and young adult females (ages 14–25) with a family history of fragile X syndrome regarding their perceptions of the optimal ages for (1) learning fragile X is inherited, (2) learning one could be a carrier for fragile X, and (3) offering carrier testing for fragile X. Three groups were enrolled: those who knew they were carriers or noncarriers and those who knew only they were at-risk to be a carrier. Only 2 of the 53 participants felt that offering carrier testing should be delayed until the age of 18 years. Participants who knew only that they were at-risk to be a carrier provided older optimal ages for offering carrier testing than those who knew their actual carrier status. Participants did not express regret or negative emotions about the timing of the disclosure of genetic risk information regarding their own experiences. Participants' reasoning behind reported ages for informing about genetic risk and offering carrier testing varied depending on what type of information was being disclosed, which carrier status group the participant belonged to, and the preferred age for learning the information. Study findings suggest that decisions regarding the timing to inform about genetic risk and offer testing should be tailored to the individual needs of the child and his/her family. © 2009 Wiley-Liss, Inc.