Smaller families in general (including the one-child option) are becoming more popular. This ERIC Digest focuses on changing trends in family size, reasons for choosing to have only one child, differences between only children and those with siblings, and the advantages of being an only child. Changing family patterns, economic concerns, and new roles for women are cited among the reasons for choosing to have only one child. Investigation results are briefly discussed regarding the only child and the following variables: intelligence, achievement, affiliation, peer popularity, and self-esteem. It is concluded that parents who chose to have only one child gain reduced conflict in dividing time and attention among children, greater financial flexibility, and a more closely knit family unit. (RH)