|Born||Penelope Jane Balchin
November 19, 1937
|Spouse(s)||Gerald Leach (1933-2004)|
|Children||Melissa A. Leach (1965)
Matthew Darian Leach (1968)
|Parents||Nigel & Elizabeth Balchin nee Walshe|
Leach is best known for her book Your Baby and Child: From Birth to Age Five, published in 1977, which has sold over two million copies to date. Leach notes in the introduction to that book: "Whatever you are doing, however you are coping, if you listen to your child and to your own feelings, there will be something you can actually do to put things right or make the best of those that are wrong."
Early career 
She is the daughter of Nigel Balchin, the novelist and screenwriter. She graduated from Newnham College, Cambridge with honours in 1959. After Cambridge, she attended the London School of Economics, where she received her Ph.D. in psychology and lectured on child development. Her research positions have included a year in the Home Office Research Unit studying juvenile crime and six years at the Medical Research Centre Developmental Research Unit. Leach is a fellow of the British Psychological Society and was previously President of the National Childminding Association.
Books and Media 
Your Baby and Child 
Leach's most popular work is Your Baby and Child, which appeared in extensively revised versions in 1988 and 1997. The most recent third edition of the book is divided into five major sections, covering newborns, "settled babies," "older babies," toddlers, and "young children." Each section includes information on expected developmental milestones and patterns in the areas of sleep, eating, "crying and comforting," speech, and physical growth. The book's central thesis is to illuminate "the successive tasks of development with which [children] are involved, the kinds of thought of which they are capable and the extremes of emotion that carry them along" because "the happier you can make your baby, the more you will enjoy being with her, and the more you enjoy her, the happier she will be."
Other works 
- Babyhood (1974, rev. 1983) is a treatment of academic research on child development presented for a lay audience.
- Your Growing Child (1986), originally published as The Child Care Encyclopedia, is a medical reference book for parents.
- The First Six Months: Getting Together With Your Baby (1986) takes a similar approach to Your Baby and Child, with a special emphasis on the newborn.
- Children First: What Society Must Do --- And Is Not Doing --- For Children Today (1994) is a polemic suggesting large-scale social initiatives to end child poverty and homelessness, and to enable parents to spend more time with their children.
- Child Care Today (Alfred A. Knopf, 2009) 
Leach has also produced several home videos (Becoming a Family, Baby to Toddler, and 'Toddler to Child') as well as a play called Snap Happy that toured schools to teach conflict resolution to preschool and school-aged children.
Current projects 
Leach's major current project is directing a large-scale United Kingdom project on the longitudinal effects of various forms of daycare and childcare on children and their parents. She also serves on the curriculum board for Sesame Street and writes parenting advice columns for several publications, including Junior Magazine and the website BabyCenter.
Leach has been criticized heavily for her view that only mothers can care for children. Criticism has focused on (a) Leach appearing lack a grasp, perhaps because of unresolved trauma in her past, of how children see their fathers, the help that many fathers provide children in child care, and what children need from fathers, particularly those that live in the home and (b) Leach holding an authoritarian, unsupported opposition to child care and an inability to recognize its benefits.
The second daughter of the novelist Nigel Balchin, in 1963 she married the science journalist Gerald A. Leach (1933-2004) with children:
- Melissa A. Leach (1965-)
- Matthew Darian Leach (1968-)
- GRO Register of Births: MAR 1938 1a 808 HAMPSTEAD - Penelope J. Balchin, mmn = Walshe
- Lawson, Carol (June 13, 1991). "Growing Up With Help From Penelope Leach". New York Times. Retrieved 26 December 2012.
- Morrison, Blake (April 17, 1994). "She Who Must Be Obeyed: Penelope Leach, scourge of the guilty middle-class parent, has produced another book. Baby and Child became the child-rearers' bible. Children First is a manifesto for children's rights". The Independent. Retrieved 26 December 2012.
- Eyer, Diane E. (1997). In Mary Roth Walsh. Women, Men & Gender. Yale University Press. p. 3730382. ISBN 978-0300069389.