The adage "less is more" is taking on a more profound meaning when it comes to the way modern couples go about family planning.
Although a century ago, social stigma and stereotypes swirled around single-child families, today having only one child is becoming increasingly viewed as a common-sense decision rather than a sorrowful circumstance or an act of selfishness.
The perception of only-child families as "unfortunate" can be traced to Granville Stanley Hall, most notorious for his 1896 study "Of Peculiar and Exceptional Children."
This study depicted only children as oddballs and societal outcasts deprived of normalcy thanks to the lack of a sibling presence. "Being an only child is a disease in itself," he warned.
Much has been done to disprove Hall's disparaging theories, especially in the past few decades. For example, Hans-Peter Kohler, a population sociologist at the University of Pennsylvania, found in his survey of 35,000 Danish twins, that women with one child were more satisfied with their lives than women with none or more than one.
In her 1989 book, Family Size and Achievement, Judith Blake observed that "onlies" were often high-achievers academically who benefitted from the fact there was no "dilution of resources" -- parents had more time, energy and money to invest in their child's success.
As psychologists Susan Newman and Alan Singer (both who live and practice in the Philadelphia area) see it, the increase in single-child families not only reflects societal evolution, but also the fact that prospective parents are weighing their options with a better understanding of what goes into successfully raising a child.
"The one-child household is the fastest growing family unit," explains Newman. "The United States has more single-child families than those with two children. Surprising? Not when you consider general cultural trends that have affected the shape of families in the last 20 years.
"Couples are marrying later and are older when they start families. Often, it's a matter of not having the reproductive time to have multiple children. The wait means women are having first babies at ages when previous generations were on their second, third or fourth."
In her books, The Case for the Only Child, just published, and Parenting an Only Child: The Joys and Challenges of Raising Your One and Only, Newman details how the prevalence of women with higher levels of education and a greater variety of career options have greatly altered childbearing patterns.
There is also the reality that there are now a couple of generations of women who want more out of their lives beyond raising children, argues Newman.
Adding to that is the fact that many women are realistic in understanding they can't do it all, and don't want to spread themselves thin.
"A job can be the thing that dissolves doubt. The impact of a second maternity leave, for example, can be extensive, particularly in the current economic climate. There is a 'Motherhood Penalty' in real dollars and in job security."
The Case for the Only Child rationale for having one child has a strong statistical basis as well. The National Center for Health Statistics states that between 1980 and 2004, the number of women giving birth at age 30 has doubled; at age 35, tripled; and after age 40 has almost quadrupled.
Those who wait until they are older often face infertility or secondary infertility. Age limits for parents can be a significant impediment to adopting a second child, too.
Singer, who balances being a father with his work as family therapist, creator ofFamilyThinking.com, and author of Creating Your Perfect Family Size: How to Make An Informed Decision About Having a Baby, cites recent U.S. census data that supports the slow-but-sure evolution of this trend and the argument that "one-and-done" is the right decision for many couples.
"What upset me most was that people's marriages were put into jeopardy because of external forces being exerted" to have kids, says Singer.
"Bad reasons include giving in to pressure to give their parents grandchildren, or having children because everybody else they know has children, or as the Pew Research Center found in a survey of 1,000 people conducted about a year ago, a third of those surveyed effectively had children 'just because,' and that scares me to death."
He has also found through his own work and through the research of colleagues that most of the "only" children are very well-adjusted, do well in school and have no issue with being an only child.
On the other hand, he notes, parents, regardless of the number of children they have, can be over-controlling, spoiling or neglectful.
"Though my husband Chris and I considered two children, we stuck with one," says Frances Janisch, a client of Singer. "While our decision was purely economic, we can assure our daughter the best education and quality of life possible."
Meanwhile, "the era of getting married and the requisite two children is long gone," affirms Newman.
"Family has new definitions that include single parents, gay and lesbian parents, and, of course, one child. The decline in marriage, the number of single women having babies, women in the workforce, the difficulties and expense of adoption and infertility technology -- all point to more one-child families."