In France, suicide is the second leading cause of death among the 14-22 years population. Suicide behavior (SB) spans a spectrum ranging from suicidal ideation to suicide attempts and completed suicide. Several factors likely determine the predisposition to SB, including biological factors and psychosocial stressors. For biological factors, convergent evidence from adoption, family, and twin studies of suicide strongly suggests genetic contributions to liability for SB. Although genetic factors play a role in SB, identifying specific genes involved has proved challenging. Molecular-genetic technologies have made great advances in the past decade, including genome- wide searches for disease-causing genes with the linkage disequilibrium (LD) approach. Despite being a major public health problem in the youth population, genetic associations studies regarding suicidal behavior in adolescence are still rare. Genes that code for proteins involved in regulating serotonergic neurotransmission have thus been major candidate genes for association studies of SB. Among them, genes for serotonin metabolism (tryptophan hydroxylase, TPH), serotonin transport (5-HTT), and the serotonergic 2A (5-HT2A) receptor have received the most research attention.