This article discusses the research of genes that may be involved in suicide predisposition. The evidence supporting the role of genes in suicide is based on the following: 1) suicide often runs in families, & 2) twin & adoption studies suggest that genes are likely to account for familial clustering of suicidal behaviour. A study was done which indicated that individuals with a certain regulatory variant of the serotonin transporter gene are more likely to display suicidal behaviour when exposed to life stressors. These results need to be replicated & better investigated. (LC) (8 refs)