It has been known for a while now, but not fully understood why, that the age of parents can have an effect on the child's chance of being on the autism spectrum. The full reasons why are not known, but there are some ideas. To examine the potential reasons, recently a study looked at behavioral development in children and how it relates to the age of the father.
Not terribly surprisingly, it does have an effect. The particular effects, however, were a little different than expected. Not startlingly so, but a good cause for more research. We will go through the study and the conclusions below.
Magdalena Janecka, PhD, led the study. It involved 15,000 twins from the United Kingdom, followed from the age of 4 until they reached 16. The father's age at conception was recorded. Factors they looked for included positive social skills, hyperactivity, emotionality, and whether the children could get along with their peers.
The main method of acquiring information about the children’s behavioral development was through the use of a test called the Strengths and Difficulties Questionnaire. The usage twins came from an effort in Britain called the Twins Early Development Study, also known as TEDS.
TEDS was a collection of data that had already been gathered for other purposes. It was focused on skills relating to social functioning, and measured children at ages four, seven, nine, fourteen, and sixteen. This study took that information and excluded children who were diagnosed with autism or had other factors which were known to affect development, such as premature birth and alcohol use by the mother.
Previous research had shown that children of older fathers or younger mothers had a higher chance of developing autism. This study looked at the general population to see if there was any link between this chance of autism and social development in people without autism.
Basically, they were wondering if the reason why the father's age mattered was because of the father's genetics or because of environmental factors.
The study was funded by the Seaver Autism Centre for Research and Treatment at the Icahn School of Medicine at Mount Sinai. The Icahn School of Medicine at Mount Sinai (located in Manhattan) is internationally well regarded as a research institution.
The full title of the study is Paternal Age Alters Social Development in Offspring. The researchers were Magdalena Janecka, Claire M.A. Haworth, Angelica Ronald, Eva Krapohl, Francesca Happé, Jonathan Mill, Leonard C. Schalkwyk, Cathy Fernandes, Abraham Reichenberg, and Frühling Rijsdijk.
The age of the father at conception had an effect on the social development of the children. What is interesting is that this is not a linear relationship. Both older fathers and particularly young fathers were associated with a lack of social development. Fathers aged between 25 and 51 did not have the same effect.
Also interesting is that the social development, while overall diminished, was stronger in the children of the young or old fathers when the children were young. By the time they became adolescents, however, the children of these fathers had fallen behind their peers in their ability to use social skills.
Also, while other behavioral development was examined, only social development was affected by the father's age. Hyperactivity, conduct, peer relationships, and emotional expression were unaffected by the age of the father at conception.
When looking at genetic or environmental factors, the researchers came to the conclusion that social skill development was more effected by genetics than the environment. However, the importance of the genetic factors was more important to the children of the older fathers, not as important in the development of the children from younger fathers.
The Mother's Effect
Though it was not the focus of the study, the researchers gathered data about the age of the mother at conception as well. They were able to examine this data and put together some conclusions.
Very young mothers had an effect on their child's development, and not just socially. Children born to mothers under 21 were often more hyperactive, had problems conducting themselves properly, and were less likely to be able to express their emotions.
It was known from previous studies that the risk of autism increased for both young and old mothers. Younger parents often have sub-optimal pregnancies, either from not being as healthy or because the mother's body is not fully developed. The data from this study helped the researchers to understand that the increase for young mothers is not just environmental but also is partially genetic.
Dr. Janecka would like to replicate the findings with another study, as that is very important for scientific credibility. She would also like to find the biological factors which contribute to the effects she observed.
She has an idea that the social skill development is affected by how the child's brain matures, and is curious as to how the age of the father has that effect. Following this chain to its source may eventually lead her or another researcher to learn the reasons which contribute to why some children develop autism.
A Note on Risk Factors
So, it has been established that the age of the father is a risk factor for a lack of social skill development and even potential autism in their children. If you are a parent or will become one soon, please do not use this information to panic!
It is important to realize that there are few words which researchers throw around which can be alarming to the casual reader, but are not as dangerous once you have learned about them. What we are talking about this time is the term 'risk factor'.
Correlation does not equal causation. Risk factors show a correlation between a variable and a result such as a disease. This correlation does not mean that the risk factor causes the disease.
Risk factors, however, can provide something for those in the medical professions to watch out for. If your doctor knows the risk factors you fall into, they will be able to more easily catch or prevent diseases.
Also, risk factors show potential links, through which researchers may be able to figure out what causes the disease in question. In this study, the researchers identified several age groups as potential risk factors, and hope to use these to explore what is causing the lack of social development later. Science is a slow, incremental process.
Very old or very young fathers tend to produce children who start off strong with their social skills but drop off in their social development by adolescence. Should you be worried about this and how it might relate to your child? Probably not.
The children were not stunted in their social skills, just different. This is just one of those small effects of life which help people to be different from one another. The social skill development did not correlate to a lack of development in other fields. There is nothing to worry about.
However, for researchers interested in tackling the question of what causes autism, this is an exciting study. It is one more step on the long path to learning what causes the disorder, and every little thing we learn can help someone with autism or their support system in the future.