Are only children spoiled, selfish and lonely, or smarter and more loving?
The number of American women who have only one child has doubled over the last two decades, even though only children often bear the brunt of nasty stereotypes.
The assessment is not necessarily true, said psychologist Susan Newman, author of the book "Parenting an Only Child."
Many studies show that only children are no more self-centered or spoiled than others, Newman said. Some studies suggest only kids tend to have closer, more affectionate relationships with their parents than kids from bigger families.
Only children often develop better verbal skills and excel in school because they are read to more often than children with siblings, she said.
Only children also tend to have higher IQs, which researchers say may be because their parents have higher expectations for them and more time and money to give.
According to the U.S. Department of Labor, for families that make roughly $60,000 a year, each child costs more than $250,000 by the time he or she reaches 18, and that doesn't include college costs.
Newman said children cost their parents $50,000 in food alone by the time they hit 18.
"Twenty percent of the family population is one child," Newman said. "In the major metropolitan cities, like New York and Los Angeles, that number is 30 percent. People are having children later, which leaves less time for having the second child. Housing is expensive. The divorce rate hovers at 50 percent. Often both parents are working, and child care is a factor."
Children from larger families also enjoy some advantages, which include having playmates and tormenters, teammates and rivals. Siblings define each other and teach each other conflict resolution, which is a skill people bring to their workplaces, marriages and other relationships.
If a couple decides to have only one child, Newman said, they should make sure the child has sibling substitutes from whom to learn sharing, empathy and conflict resolution.
With all these things to consider, Newman said, the most important factor in deciding whether to have one or more than one child is what the parents want.
"The ideal number of children is the number that you and your partner agree on, and that won't overwhelm and tax you or stretch you so thin that you are always in a panic," she said. "And that's a choice that will be different for every couple."
Newman talked to ABC News' Bill Weir, the father of one daughter, and JuJu Chang, the mother of two sons, ages 2 and 5.
"I want to have three, but my husband wants the two," Chang said. "The boys are 5 and 2. It's one of the few points of conflict between me and my husband. My husband's famous joke is we'll go from a man-to-man defense to having to play a zone defense, meaning that we'll be outnumbered by our kids. Also, in New York City, five people can't get into one cab."
"You'll be quadrupling the work load," Newman told her. "And there you're having a middle child. And it takes very conscientious parenting skills to make that middle child feel special. You want to give that middle child extra attention. And then ... you have to worry about two boys versus one girl."
Newman said that having two children triples the work load because parents have to spend time with both children and with each child individually. It grows exponentially like that with each added child, she said.
Weir, who grew up an only child until age 17, said he loved the experience and would like his daughter to enjoy it.
His wife, however, has different ideas. Newman said people often want to emulate the experience they had if it was positive or do the complete opposite if it was negative.
In the end, she said, parenting is much more important than the number of siblings.