Norms are considered to influence expectations toward gender-related behavior. Deviations from these norms are often perceived negatively by the social environment. The objective of this study was to investigate adults diagnosed with a Gender Identity Disorder (GID), their recalled play behavior, and peer preferences in childhood and adolescence. Differences between individuals who applied for transition from female to male (FtMs) and those who applied for transition from male to female (MtFs) and between age-of-onset subgroups were explored. Data collection took place as part of the European Network for the Investigation of Gender Incongruence. The sample consisted of N = 634 participants (mean age = 30.6) diagnosed with GID according to DSM-IV-TR who were recruited between 2007 and 2012. Participants answered two questions regarding recalled play behavior and three questions on peer preferences. Nonconforming gender expression was more frequently recalled in FtMs than MtFs. Within gender groups, individuals who were categorized as early-onset recalled nonconforming gender expression more frequently than individuals who were categorized as late-onset. The results of the study are in line with previous findings indicating different phenomenological pathways in individuals applying for gender-affirming treatment that warrant attention. Factors that are considered to impact on gender-related differences in nonconforming gender expression are discussed.