The diagnosis of Lynch syndrome can lead to the prevention of colorectal cancer through periodic colonoscopies and removal of premalignant lesions in susceptible individuals. Therefore, predisposed individuals identified by mutation analysis are advised to inform their at-risk relatives about the options of predictive DNA testing and preventive measures. However, it has now been established that more than half of these relatives do not receive the necessary information. Barriers in conveying information include family communication problems and variable attitudes and practice among clinical geneticists. In this complex field, both medical, psychological, ethical and juridical aspects deserve consideration. Here we summarize the development of a revised guideline for clinical geneticists that allows a more active role of the geneticist, aimed at improving procedures to inform family members in Lynch syndrome and other hereditary and familial cancer syndromes. © 2013 Springer Science+Business Media Dordrecht.