According to new data, the average age of new fathers in the United States has increased by three and a half years in the last four decades. Today, there are more fathers of newborns that are over 40 and 50 years of age.

Increased Paternal Age

Researchers from Stanford University School of Medicine conducted a comprehensive study regarding the age of fathers in the United States from 1972 to 2015. Although it is often women who are studied when it comes to their childbearing age, it seems as though men have also begun to put off having kids until a later age.

Using data from the National Vital Statistics System, researchers analyzed data from 168,867,480 births between 1972 and 2015. What they found was that the average age of the fathers of newborns in the United States has increased by three and a half years and even more for Asian-American fathers.

Paternal Age And Education

In 1972, fathers of newborns had an average age of 27.4, whereas the average paternal age today is 30.9. Further, Asian-American dads are the oldest among the fathers of newborns, with an average age of 36. More prone to this trend are Vietnamese-American and Japanese-American dads.

In addition, during the 44-year period, the number of newborns' fathers over 40 years old actually doubled from 4.1 to 8.9 percent, while fathers of newborns over the age of 50 increased from 0.5 to 0.9 percent. Interestingly, educational levels also had an effect on paternal age, as the average age of college-educated fathers was found to be 33.3 years old.

The youngest father in the 44-year data was 11 years old, while the oldest father was 88 years old.

Health Implications

Researchers believe that just like women, men's paternal age also has an effect on their offspring. For instance, the number of children a man will have may also depend on his paternal age, thereby affecting the population.

Research has also previously shown an association between older fatherhood and increased chances of autism, chromosomal abnormalities, rare genetic conditions, schizophrenia, and certain pediatric cancers. What's more, every man is expected to have an average of two mutations in his sperm each year.

Despite this, researchers also note that older fathers have more access to resources, better jobs, stable lifestyles, live with their children, and are more involved in child-rearing. Further, a previous study also showed that older fathers tend to have socially awkward but intellectual sons.

Moms And Dads

It seems both moms and dads are putting off having children because the data also provide evidence for increasing maternal age. In fact, the 44-year data shows that the age difference between moms and dads have also decreased from 2.7 to 2.3 years.

Researchers surmise that the change is perhaps due to the rising number of women who are placing great importance to their careers and the availability of reliable contraception.

Results of the study were published in Human Reproduction.