by Bryan Caplan
A TALE OF TWO SONOGRAMS
I’ll never forget my wife’s first sonogram. The technician stared at the monitor while she asked my wife boilerplate questions about her medical history.
“How long have you been pregnant?”
“About twelve weeks.”
“Morning sickness?”
“A little.”
“Any family history of genetic diseases?”
“No.”
“Any history of twins?”
“No.”
“Well, you’re having twins.”
My eyes bugged out. I was pretty sure a twin hoax would be a firing offense, but I still stammered, “You wouldn’t joke about something like that? . . .” When the tech showed me the screen, my eyes bugged out a little more. There they were: two tiny bodies with massive heads. As I drove back to work, I was pale white. Two kids—what were we going to do?
Seven years later, my wife was pregnant again. This time, I hoped for twins. I proposed baby names in pairs. The thought of triplets didn’t faze me. Before the sonogram technician turned on the machine, I asked for an ASAP answer to our burning question: Are there more multiples in our future? Five minutes later, we had our answer: No. We were going to be a family of five, not six or seven. I was delighted to have another healthy child on the way but couldn’t help but feel slightly disappointed.
Why was I so afraid of twins the first time around—and so hopeful the next? What did I learn between the two pregnancies? In part, I gained self-knowledge. I expected to like playing with my kids, but I didn’t realize that taking care of them would be so satisfying. When the twins outgrew their 2:00 AM feeding, I kind of missed it.
Yet most of what I figured out between the sonograms was not about my personality, but about the link between science and life. Before I became a dad, the conflict between my book learning and modern parenting was purely academic. After I became a dad, the conflict suddenly became very practical. Belief in the power of nurture inspired other parents to make painful sacrifices for their children—and dread the thought of another baby. Wouldn’t it stand to reason, then, that my disbelief in the power of nurture ought to inspire me to avoid painful sacrifices for my children—and welcome the thought of another baby?
Although parents rarely had solid answers to my questions, it seemed rash to dismiss their firsthand experience. Maybe parents saw crucial facts that researchers missed. By the time our twins were toddlers, however, I realized that I didn’t need to discount anyone’s experiences. Parents heavily influence their kids in many ways; they see it with their own eyes. Their mistake is to assume that their influence lasts a lifetime, instead of fading out as their kids grow up.
Once I reconciled my book learning with my firsthand experience, I had a lot to reconsider—starting with our first fateful sonogram. My knee-jerk reaction was dead wrong. I should have been thrilled to get two kids for the price of one. While my wife and I could have made ourselves miserable by mindlessly doubling all the standard parental sacrifices, we compromised on a more relaxed approach. We spent money to make our lives easier. We didn’t struggle to put our twins in the best preschool or peewee chess championship. We let them watch TV. Twins were a little tiring at first, but I kept my 2:00 AM double feedings in perspective. The extra start-up costs were modest—and these kids would be ours for the rest of our lives.
That’s why I went to our second big sonogram hoping for twins. Would four kids ruin our lives? That was up to us. How would we handle another set of twins? The same way we handled the first set: Work a little harder for a year or so—and remember that parenting is graded pass/fail. When the sonogram showed a healthy singleton, I had to fight the temptation to tell my wife, “Better luck next time.” I counted my blessings, but never felt relieved.
I can tell you what I learned between those two sonograms while standing on one foot: There’s no substitute for reasonable expectations. If you imagine that your children’s future is in your hands, and single-mindedly do “whatever is best for your kids,” then one child is more than enough to ruin your life. But once you accept that your children’s future is largely up to them and remember that your happiness counts, too, an unplanned set of twins is no big deal. Before long, you’ll probably think they’re the best thing that ever happened to you. I know we did.
NOTES
INTRODUCTION
1 In 1976, 20 percent of women: “Supplemental Table 2, Distribution of Women 40 to 44 Years Old by Number of Children Ever Born and Marital Status: Selected Years, 1970 to 2006,” U.S. Census Bureau, 2008.
1 the Greeks blame air pollution: Russell Shorto, “No Babies?” New York Times Magazine, June 29, 2008.
3 parental effort is at an all-time high: See, for example, Suzanne Bianchi et al., Changing Rhythms of American Family Life (New York: Russell Sage Foundation Publications, 2006).
4 A small army of researchers has compared adoptees to their relatives: For introductions to twin and adoption research, see, for example, Nancy Segal, Entwined Lives: Twins and What They Tell Us About Human Behavior (New York: Plume, 1999); Judith Harris, The Nurture Assumption: Why Children Turn out the Way They Do (New York: Free Press, 1998); and David Rowe, The Limits of Family Influence (New York: Guilford Press, 1994).
6 Children under five years old are almost five times as safe: See Vital Statistics of the United States 1950, Volume 3, Mortality Data, Table 57, U.S. Department of Health, Education, and Welfare, 1953, available at www.nber.org/vital-statistics/historical/vsus_1950_3.pdf; and “National Vital Statistics Reports, Deaths, Final Data for 2005,” Centers for Disease Control and Prevention, 2008, Table 11, available at www.cdc.gov/nchs/data/nvsr/nvsr56/nvsr56_10.pdf.
8 Back in 1940, America had almost ten workers per retiree: “Social Security Area Population Projections: 1997,” Social Security Administration, Figure 8, available at www.ssa.gov/OACT/NOTES/pdf_studies/study112.pdf; “Table V.A2—Social Security Area Population as of July 1 and Dependency Ratios,” Social Security Administration 2002, available at www.ssa.gov/OACT/TR/TR02/lr5A2–2.html.
8 Air and water quality have improved: For good introductions, see Julian Simon, The Ultimate Resource 2 (Princeton: Princeton University Press, 1996), pp. 241–257; and Bjorn Lomborg, The Skeptical Environmentalist: Measuring the Real State of the World (Cambridge: Cambridge University Press, 2001), pp. 163–177, 189–205.
8 Carbon dioxide emissions . . . are still on the rise: “Millennium Development Goals Indicators: Carbon Dioxide Emissions,” United Nations Statistics Division, 2010, available at mdgs.un.org/unsd/mdg/SeriesDetail.aspx?srid=749 .
9 About 80 percent of Americans twenty-five and older: General Social Survey, 2008. Variable identifier CHILDS.
10 a chapter for every reason you’ve heard not to have a child: Diana Dell and Suzan Erem, Do I Want To Be a Mom? A Woman’s Guide to the Decision of a Lifetime (New York: McGraw-Hill, 2003).
CHAPTER 1
14 Do I Want to Be a Mom? ominously warns: Dell and Erem, Do I Want To Be a Mom? p. 1.
14 in 1976, Newsday commissioned the highest-quality survey: “91% Would Have Children (Take That, Ann Landers),” Newsday, June 13, 1976. For a discussion of the background behind the Newsday survey and the famous Ann Landers survey that inspired it, see David Bellhouse, “Ann Landers Survey on Parenthood,” available at Nicholas R. Miller Web page, userpages .umbc.edu/~nmiller/POLI300/stat353annlanders.pdf.
15 In 2003, Gallup asked childless adults: Frank Newport, “Desire to Have Children Alive and Well in America,” Gallup Poll, April 19, 2003, available at www.gallup.com/poll/9091/desire-children-alive-well-america.aspx. A common objection to these results is that infertility inflates the measured regret of the childless. True enough, but by the same logic, unplanned pregnancies inflate parents’ measured regret. It is also worth pointing out that people are often infertile because they waited too long to have kids.
15 surveys have spent decades asking . . . “How happy are you?”: For good introductio
ns, see Daniel Gilbert, Stumbling on Happiness (New York: Knopf, 2007); and Arthur Brooks, Gross National Happiness (New York: Basic Books, 2008).
15 Before you join the “children make us miserable” chorus: This is how blogger Will Wilkinson sums up the happiness research: “Children Make Us Miserable,” available at www.willwilkinson.net/flybottle/2008/04/04/children-make-us-miserable, August 4, 2008.
15 every child makes you about 1 percentage point less likely: 1.3 percentage points, to be precise. You can check all of my General Social Survey results online at the Survey Documentation and Analysis Archive, available at sda.berkeley.edu/cgi-bin/hsda?harcsda+gss08 . First, define VERYHAPPY (which equals 1 if HAPPY=1, and 0 otherwise) and MARRIED (which equals 1 if MARITAL=1, and 0 otherwise). Then regress VERYHAPPY on MARRIED, AGE, ATTEND, and CHILDS.
16 Otherwise identical people who have one child instead of none: To check this result, define ZEROKIDS (which equals 1 if CHILDS=0, and 1 otherwise). Then regress VERYHAPPY on MARRIED, AGE, ATTEND, ZEROKIDS, and CHILDS. The estimated effect of the first child on the probability of being very happy is the coefficient on CHILDS minus the coefficient on ZEROKIDS.
16 many things in a parent’s life that bring great joy: Brooks, Gross National Happiness, p. 66.
17 Nobel laureate Daniel Kahneman . . . study of working moms: Daniel Kahneman et al., “A Survey Method for Characterizing Daily Life Experience: The Day Reconstruction Method,” Science 306 (5702) (December 2004), pp. 1776–1780.
17 “an act of parenting makes most people about as happy as”: Daniel Gilbert, “Does Fatherhood Make You Happy?” Time, June 11, 2006.
17 “When researchers ask parents what they enjoy”: “The Joys of Parenthood,” Economist, March 27, 2008.
17 Yet even he looks at these very numbers and concludes: Brooks, Gross National Happiness, p. 67.
18 Child care isn’t a picnic, but it beats a paying job: Also worth noting: A similar study (Mathew White and Paul Dolan, “Accounting for the Richness of Daily Activities,” Psychological Science 20 (8) (August 2009), pp. 1000–1008) asked participants to rate how pleasurable and rewarding their activities were. Spending time with your children turns out to be below average in pleasure but above average in reward.
18 “When people think about their offspring”: Gilbert, Stumbling on Happiness, p. 242.
18 “Although parenting has many rewarding moments”: Ibid., p. 244.
20 Back in 1965, when the typical mom was a housewife: Bianchi et al., Changing Rhythms of American Family Life, p. 63.
20 Stay-at-home moms went from about: Ibid., p. 76.
20 Parents in 2000 spent about 25 percent fewer hours with each other: Ibid., p. 104.
22 “Sleep is a negotiation”: Joshua Gans, Parentonomics: An Economist Dad Looks at Parenting (Boston: MIT Press, 2009), p. 26.
23 It works, but it’s harsh: For a good survey, see Jodi Mindell et al., “Behavioral Treatment of Bedtime Problems and Night Wakings in Infants and Young Children,” Sleep 29 (10) (2006), pp. 1263–1276.
23 The Ferber method . . . works wonders, too: Mindell et al., “Behavioral Treatment of Bedtime Problems and Night Wakings.”
24 “Find one thing you’ve pushed your kids to do”: Lenore Skenazy, Free-Range Kids: Giving Our Kids the Freedom We Had Without Going Nuts with Worry (San Francisco: Jossey-Bass, 2009), p. 124.
27 They call it “behavioral parent training”: See Anne Shaffer et al., “The Past, Present, and Future of Behavioral Parent Training: Interventions for Child and Adolescent Problem Behavior,” Behavioral Analyst Today 2 (2) (April 2001), pp. 91–106; Michelle Wierson and Rex Forehand, “Parent Behavioral Training for Child Noncompliance: Rationale, Concepts, and Effectiveness,” Current Directions in Psychological Science 3 (5) (October 1994), pp. 146–150; Anthony Graziano and David Diament, “Parent Behavioral Training: An Examination of the Paradigm,” Behavioral Modification 16 (1) (January 1992), pp. 3–38.
27 Experiments typically find that the average child of the trained parents: Wendy Serketish and Jean Dumas, “The Effectiveness of Behavioral Parent Training to Modify Antisocial Behavior in Children,” Behavior Therapy 27 (2) (Spring 1996), pp. 171–186. See also Sheila Eyberg et al., “Evidence-Based Psychosocial Treatments for Children and Adolescents with Disruptive Behavior,” Journal of Clinical Child and Adolescent Psychology 37 (1) (January 2008), pp. 215–237.
27 The main weakness of the training: Shaffer et al., “The Past, Present, and Future of Behavioral Parent Training.”
27 A central criticism of behavioral parent training: See, for example, Judith Harris, No Two Alike (New York: W. W. Norton, 2007), pp. 130–135.
28 Yet when Skenazy bragged about his odyssey: For Skenazy’s full story, see Free-Range Kids, pp. xiii–xvi.
29 “Volunteer to watch the kids who are waiting”: Ibid., pp. 58, 102, 143.
31 Using money to make parenting easier: I separately regressed VERYHAPPY on MARRIED, AGE, ATTEND, ZEROKIDS, and CHILDS on the bottom and top halves of REALINC. For the bottom half of the income distribution, ZEROKIDS has a coefficient of .061, versus .030 for the top half. (The coefficients on CHILDS were the same: .006.) One tempting explanation for this pattern is simply that higher-income people are more careful to avoid unwanted pregnancies. Remember, however, that these results already control for age and marriage—which are presumably the main predictors of whether or not a pregnancy is wanted.
33 Overall, parents did pretty well: Ellen Galinsky, Ask the Children: What America’s Children Really Think About Working Parents (New York: William Morrow, 1999), pp. 46–47.
CHAPTER 2
40 When a couple raises the child of a perfect stranger: The main caveat is that some adoption agencies use “selective placement”—they try to match adoptees with families similar to their biological families in socioeconomic status, religion, and more. When you compare adoptees to their adopted families, selective placement makes nurture effects look larger and nature effects look smaller than they really are. When you compare adoptees to their biological families, selective placement makes nurture effects look smaller and nature effects look bigger than they really are. For further explanation, see Joseph Horn, “The Texas Adoption Project: Adopted Children and Their Intellectual Resemblance to Biological and Adoptive Parents,” Child Development 54 (2) (April 1983), pp. 268–275.
42 If parents’ income, education, marital status, parenting philosophy, religion: A few studies split this blanket “nurture effect” into more specific components, such as parental influence, sibling influence, and special twin environments. But most data sets do not have enough information to disentangle these effects.
42 you could just as well say “none of the above”: I owe the “none of the above” label to Judith Harris’s The Nurture Assumption. Harris’s No Two Alike critiques leading accounts of unique environment and offers her own.
47 One looked at almost 3,000 pairs of Danish twins: Anne Herskind et al., “The Heritability of Human Longevity: A Population-Based Study of 2872 Danish Twin Pairs Born 1870–1900,” Human Genetics 97 (3) (March 1996), pp. 319–323.
47 Yet the Danish twin study found: Ibid., p. 319.
47 Another study looked at the mortality of about 9,000 Swedish twins: Anatoli Yashin et al., “Half of the Variation in Susceptibility to Mortality Is Genetic: Findings from Swedish Twin Survival Data,” Behavior Genetics 29 (1) (January 1999), pp. 11–19.
47 A study of over 3,000 elderly Danish twins: Kaare Christensen et al., “A Danish Population-Based Twin Study on General Health in the Elderly,” Journal of Aging and Health 11 (1) (February 1999), pp. 49–64.
47 Another team of researchers looked at about 2,500 Swedish twins: Pia Svedberg et al., “Age and Sex Differences in Genetic and Environmental Factors for Self-Rated Health: A Twin Study,” Journal of Gerontology 56 (3) (May 2001), pp. 171–178.
47 A smaller study of older female Finnish twins: Raija Leinonen et al., “Genetic Influences Underlying Self-Rated Health in Older
Female Twins,” Journal of the American Geriatrics Society 53 (6) (June 2005), pp. 1002–1007.
47 notable exception comes from the Swedish Adoption/Twin Study of Aging: Jennifer Harris et al., “Age Differences in Genetic and Environmental Influences for Health from the Swedish Adoption/Twin Study of Aging,” Journal of Gerontology 47 (3) (May 1992), pp. 213–220.
48 In the Swedish Adoption/Twin Study of Aging, twins raised together: Ibid., pp. 216–217.
48 A major survey article on the genetics of obesity: John Hewitt, “The Genetics of Obesity: What Have Genetic Studies Told Us About the Environment?” Behavior Genetics 27 (4) (July 1997), pp. 353–358, cites several studies finding a lack of parental influence even for young children; Kelly Klump et al., “Age Differences in Genetic and Environmental Influences on Eating Attitudes and Behaviors in Preadolescent and Adolescent Female Twins,” Journal of Abnormal Psychology 109 (2) (May 2000), pp. 239–251, find an effect of shared environment for eleven-year-olds but not seventeen-year-olds.
