All Parents Are Environmentalists Until They Have Their Second Child

Marvin Zuckerman? Kelvin L. Seifert? David T. Lykken? Anonymous?

Dear Quote Investigator: A child’s development is influenced by both nature and nurture, but there are deep disagreements about the relative importance of these two influences. In addition, there are different viewpoints concerning the interactions of nature and nurture. Consider the following saying:

The parents of one child believe in “nurture”, and the parents of two or more children believe in “nature”.

When parents have one child it is easy for them to postulate that their actions are precisely guiding the development of their child. However, this belief is challenged when a second child is born, and the same actions yield sharply divergent results. Would you please help me to trace this saying?

Quote Investigator: The earliest match located by QI appeared in a scientific journal in 1987. To understand this match one must be aware of the different meanings of the word “environmentalist”. The word typically describes a person who wishes to protect the ecology of biomes. But in this article it refers to a person who believes that human development is predominantly shaped by environmental factors such as parenting style, surroundings, and experiences. The effects of heredity are minimized.

University of Delaware psychologist Marvin Zuckerman published a piece in the journal “Behavioral and Brain Sciences” with a title matching the remark under exploration. Boldface added to excerpts by QI: 1

All parents are environmentalists until they have their second child

Zuckerman’s article began with the following sentences:

What is it that happens to parents after they have their second child that shakes their belief in the tabula rasa? With an n of one, parents can assume that all of their child’s positive traits are due to their enlightened methods of child rearing (negative traits being assigned to a genetic influence from other relatives). Then they use the same methods with the second child, who turns out to be so different from the first that they have to question their premises.

Below are additional selected citations in chronological order.

A thematically related remark appeared in a 1946 pamphlet titled “Parent Education Through Home and School”. A section written by Reverend James A. Magner began with the following passage: 2

“Before I got married,” wrote Lord Rochester, “I had six theories about bringing up children. Now I have six children—and no theories.”

This saying is explored in a separate QI article located here.

In 1987 a match occurred in the title of an article by Marvin Zuckerman as mentioned previously.

In 1997 “Lifespan Development” by Kelvin L. Seifert et al included the following version of the saying with an anonymous attribution: 3

A psychologist once said that “every parent believes in nurture until they have their second child.” What do you think she was getting at with this comment? If you happen to be a parent of at least two children, share your opinion of this comment with a classmate who is not a parent or with one who is a first-time parent.

In 1998 psychologist David T. Lykken who was known for his efforts on the University of Minnesota twin studies was interviewed at the website. He employed a version of the saying: 4

The denial of genetically based psychological differences is the kind of sophisticated error normally accessible only to persons having Ph.D. degrees. Even the be-doctored tend to give up radical environmentalism once they have a second child. In our twenty-five years of twin research at Minnesota, monozygotic twins, who share all their genes, have been found to be twice (or more than twice) as similar as dizygotic twins, who share on average half their polymorphic genes, on nearly every trait that we can measure reliably.

In 2006 a commenter at the website employed an instance with an anonymous attribution: 5

To respond to the second part of the comment, it’s often said that parents of one child believe in “nurture” and parents of multiple children believe in “nature”. I have four daughters with the same biological parents, same advantages and disadvantages. Two are decent solid musicians without any particular stand-out gifts or qualities. Two are very gifted and of those two, one had focus drive and the right set of physical gifts . . .

In conclusion, currently Marvin Zuckerman deserves credit for the saying he wrote in 1987. This remark about a second child can be expressed in many different ways; hence, it is possible that the 1987 citation may be antedated by future researchers and the attribution may shift.

Image Notes: Three illustrations of 3D figures: a family, a reader, and a skateboarder from 3D_Maennchen at Pixabay.

(Great thanks to Kevin Mitchell, Cathy Barry, Timofey Pnin, and Richard Harper whose discussion and inquiry led QI to formulate this question and perform this exploration. Barry pointed to the 2006 citation, and Pnin pointed to the 1998 citation.)


  1. 1987 March, Behavioral and Brain Sciences, Volume 10, Issue 1, All parents are environmentalists until they have their second child by Marvin Zuckerman (Department of Psychology, University of Delaware, Newark, Delaware), Start Page 42, Quote Page 42, (Response article to: Why are children in the same family so different from one another? by Robert Plomin and Denise Daniels), Cambridge University Press, Cambridge, England. (Accessed via May 21, 2019) link
  2. Date: 1946, Pamphlet Title: Parent Education Through Home and School, Catalog Description from Preface: [Addresses] originally presented at the fourteenth annual meeting of the National Catholic conference on family life, held at the Catholic University of America, February 5-8, 1946, Article Title: The Social Values of the Home, Article Author: Rev. James A. Magner, Start Page 11, Quote Page 11, Publisher: N.C.W.C. Family Life Bureau, Washington, D.C. (Verified with scans; great thanks to the librarians at Logue Library of Chestnut Hill College, Philadelphia, Pennsylvania)
  3. 1997 Copyright, Lifespan Development by Kelvin L. Seifert (The University of Manitoba), Robert J. Hoffnung (University of New Haven), and Michele Hoffnung (Quinnipiac College), Chapter 1: Introduction: Studying Development, Quote Page 16, Houghton Mifflin Company, Boston, Massachusetts. (Verified with scans)
  4. Website:, Article title: How Can Educated People Continue To Be Radical Environmentalists? Article authors: A Talk With David Lykken with Introduction by John Brockman, Date on website: June 19, 1998, Website description: A living document on the Web to display the activities of “The Third Culture”; is a nonprofit private operating foundation. (Accessed on August 26, 2019) link
  5. Website:, Article title: Nurture vs. Nature, Article author: Howard Vandersluis, Article timestamp on website: September 8, 2006 at 05:11 PM, Comment author: Elizabeth Smith, Comment timestamp on website: September 19, 2006 at 01:15 PM, Website self-description: covers the classical music industry, providing news, reviews and interviews of interest to violin performers, teachers, students, and fans. More than 26,000 violinists have registered as members on (Accessed on August 26, 2019) link