Across the developed world, and even in some African nations, the average age of first-time mothers has been climbing steadily over the last three decades. In 1970, the average age of a first-time mother in the United States was 21, according to data from the Centers for Disease Control and Prevention. By 2013, the average age had risen to 26. In Japan, where the population is aging heavily, the average age is around 29.
A number of studies indicate emotional and developmental benefits for children whose parents are a little older,
say in their late 30s and early 40s.
A study by researchers at Birkbeck University of London and University College London found that maternal age ties into how successfully parents discipline their children. In their findings, older mothers were less likely to punish their children by withholding treats or attention. They were also less likely to have conflicts with their children.
The study was by no means a small one. It included carrying out home visits to almost 15,000 mothers when their children were 3 years old. The researchers noted that 48 percent of children born in England and Wales in 2010, which was the birth year of their sample children, were born to mothers over the age of 30.
In the U.S., the level of education of a mother appears to play a role in the age of her first birth. According to a Pew Research Center analysis of census data, the median age of first-time mothers with a Masters degree is 30, while the median age for first-time mothers who hold a high school diploma is 24.
Another interesting consideration is how parents of different ages respond emotionally to having a new child. A study carried out in Germany and Canada found that first-time parents over the age of 34 reported more happiness after the birth of their first child compared with their younger counterparts. In particular, younger fathers reported low levels of happiness, perhaps tied to the increased economic pressure of parenthood.
Head researcher Mikko Myrskylä, director of the Max Planck Institute for Demographic Research in Rostock in Germany, told DW.com that while the first child increases parents’ happiness fairly significantly, the second child increases happiness a little less, and the third child not really at all. He also said that the increased happiness reported by parents in the study tended to last longer for older parents.
Risks of older parenting
Being an older parent also increases the risks — albeit slightly — that a child could be born with genetic mutations. Down syndrome, for example, has a higher incidence in mothers over 35. Recent studies have suggested that older fathers’ may also carry increased risks of genetic complications.
A genome study from Iceland published in 2012 found that as men age, the number of mutations they are likely to pass on to their children also increase. The researchers were interested in establishing a link between the father’s genes and neurological disorders in children, including autism and schizophrenia.
From the findings of their study, the researchers estimated that a 36-year-old man will pass on twice as many mutations to his child compared with a 20-year-old man, and a 70-year-old will pass on eight times as many. The researchers found that regardless of their age, mothers only passed on an average of 14 mutations. The study was published online in the journal Nature.
Because fertility tends to decrease with age, older parents may face challenges trying to conceive, and seek out artificial reproductive techniques. But studies have also linked some of these artificial techniques to increased risks of deformities in children.
A University of Adelaide study published in 2012 in the New England Journal of Medicine linked the use of assisted reproduction technology to higher rates of major birth defects. The researchers linked data from more than 6,000 assisted reproduction technology births in South Australia that used techniques like IVF, ovulation induction, intracytoplasmic sperm injection (ICSI), and fresh and frozen embryo transfer.
A study from Austria published last year found that older fathers were likely to have less attractive offspring.
The researchers showed 12 people photographs of around 4,000 young men and 4,000 young women aged roughly 18-20, and asked them to rank their attractiveness. The researchers found that the photographs of people who had older fathers were rated less attractive.
Martin Fieder, an anthropologist at Vienna University, told The Sunday Times: “The effect is very visible — someone born to a father of 22 is already 5-10 per cent more attractive than those with a 40-year-old father, and the difference grows with the age gap.”