Dr. Susan Klugman, a prenatal geneticist at Mount Sinai School of Medicine in New York City, said that the study should be replicated with children born now. She noted that one complication might be that people smoked more when the data were taken, and that might have resulted in an increase in defects in the sperm.
A potential problem with reading too much into the study, noted Alan E. Kazdin, a professor of psychology and child psychiatry at Yale, is that it only followed children through the age of 7.
Because of that, he noted, some of the findings may not show what happens to these children throughout their lives.
"Older parents sometimes provide more compensatory advantages [if their financial means are better] and experiences, and that these findings, while important, did not show that the results had any practical consequences in childhood or adulthood."
Perhaps the most important result from the study, noted Mark Reinecke, chair of psychology for child development at the Northwestern University School of Medicine, is that it might alleviate the fears of older women considering having children.
To them, he said, "the findings are reassuring. A great deal has been written about the risks of having children after 40 years of age. These findings allay these concerns, at least a bit."
Reinecke noted that other factors would play a greater role in the child's ultimate success.
"Beyond this, I would emphasize the importance of maintaining a nurturing, secure, predictable, and intellectually stimulating home environment. ... That's the key during the early years," he said.
But the benefits that come with age do have a tradeoff, noted Dr. John Constantino, a child and adolescent psychiatrist at the Washington University School of Medicine in St. Louis.
"There is a point at which maternal emotional maturity gets overshadowed by increased risk of birth defects in offspring," he said.
McGrath cautioned that while his study's findings need closer scrutiny, it is too soon to make any recommendations based on it.
"I am sure your viewers and readers will want some type of guidance," he told ABCNews.com, "but, it is too early to make any recommendations. Research needs to be replicated and confirmed in different settings, etc. For the moment, our study suggests that paternal age, like maternal age, also should be 'on the radar screen' for the research community."
"As the research evidence builds, then we can put this knowledge into the public health equation. ... Our small study is one part of the jigsaw."
Michelle Schlief of ABC News contributed to this report.