For the past several days, the Times has published a series about the changing roles of mothers in the American family. Have fathers' roles changed? Who changes the diapers in your house? Who drives the children to school? Who leaves work when the children get sick? Who takes leave after the baby is born? Are American fathers as active as mothers in family life? Please send your comments to Fathers, Parental Guidance, the Times, P.O. Box 1121, St. Petersburg, FL 33731-1121, or call KidsLine, (813) 893-8985 and leave a message.