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What we do now may affect our future children’s genetics

October 15, 2014

We are all aware that mothers who smoke while they are pregnant run a higher risk of having children who are premature, smaller than they should be, or stillborn. This is likely due to reduced oxygen supply to the baby through mom’s diseased body and to toxins shared by mom with baby. We also know that children who are exposed to second-hand smoke have a higher risk of developing respiratory diseases like asthma, chronic lung disease and even cancer due to direct lung damage from inhaled smoke.

What you do with your body early in life can affect future generations

But recent data suggests that a father’s behavior even years prior to conception may affect the health of his children and future generations. For example, early paternal smoking has been associated with increased body mass in children. Paternal alcoholism has been associated with smaller birth weights in babies, and hyperactivity in children. Most recently, smoking even early in life has been found to be associated with an increased risk of certain forms of asthma in a man’s children. A study which was recently presented at the European Respiratory Society International Congress looked at 13,000 men and women and found that non-allergic asthma was significantly more common in children whose fathers smoked before the age of 15. In addition, the longer the father smoked, the higher the risk of his child having this kind of asthma. Interestingly, the same link was not found in children whose mothers smoked before they conceived.

It turns out that things we do early in life may cause chemical changes in our DNA (our genetic blueprint) that may not be totally cleaned up before egg and sperm make a baby. This growing field of study is called epigenetics. When I first heard about all of this, I thought it sounded crazy, but it turns out that there may be something to it. As I mentioned, there have been numerous studies in the past showing links between exposures and behaviors in parents and certain health risks in their children that just cannot be explained by pure heredity. What I mean by that is that we know that two blue-eyed parents will have a blue-eyed child. That is cold, hard genetics. We also know that alcoholic parents have more alcoholic children. This follows a genetic inheritance pattern as well. In other words, it is IN the DNA. But why would things like smoking as a teenager be linked to a dad’s child having asthma?

Could our future children inherit our past mistakes?

Epigenetics suggests that babies don’t only inherit our DNA. They also inherit some subtle changes that have been made to that DNA during our parents’ lives. We usually think that any little changes to our molecules get cleaned up or removed when our eggs and sperm are formed, and that all our babies get are clean copies of our genetic material. Recent studies suggest that may not be completely true. If smoking in the early teen years causes a man’s child to have an increased risk of asthma, it could be because smoking causes that man’s DNA to be chemically changed just a bit, and that those changes get passed on to his children. That is epigenetics.

We have to be careful to make assumptions here; just because there is an association between two things does not mean that one thing causes the other. For example, if we look at children of dads with alcoholism having a higher risk of ADHD, it could be because the children inherited the ADHD from their fathers, and that lack of impulse control led to the alcohol abuse in the dads. This is like assuming that flu shots give people the flu. Some people who got the flu after a flu shot were exposed to and caught the flu in the days prior to getting their flu shots. That does not mean that the shot caused the flu (it cannot, by the way). Association does not mean cause.

But the idea of epigenetics should certainly give us all pause. Not that a young man is going to avoid smoking just because it might give his as-yet-unthought-of child asthma. But how we treat our bodies certainly affects others. Smoking affects our friends and relatives by exposing them to second-hand smoke and the medical risks associated with that. It affects our loved ones as they watch us suffer and die of the complications of smoking. And now we find that smoking, even early in our lives, and even in dads who simply provide sperm to the before-birth process of a child, may affect our children for generations to come.

How we care for our bodies is important, no matter how we look at it.