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How Men’s Sperm Can Affect Pregnancy

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How Men’s Sperm Can Affect Pregnancy

May 08, 2018

From eating healthy diets to preparing the incubator, there are many things recommended to women to do before they get pregnant to have a healthy baby. But it takes two to make a baby, so what about the men? Recent research has shown that genes encoded in men’s sperm can be modifed by the environment in which they were developing, and those modifications may affect the developing child. In this episode, Dr. Kirtly Parker Jones gives insight into some of the things that men can do to prepare for pregnancy.

Episode Transcript

Dr. Jones: Plan your pregnancy. Act pregnant before you get pregnant. Prepare the incubator. These are all things we tell women to do before they get pregnant to have a healthy baby, but what about the guys? This is Dr. Kirtly Jones from obstetrics and gynecology at University of Utah Health and we're talking about men, sperm, and the babies they make on The Scope.

Announcer: Covering all aspects of women's health. This is the Seven Domains of Women's Health with Dr. Kirtly Jones on The Scope.

In the past 20 years, we've been learning about changes to genes that happen very early in development, very early. As early as the first week after fertilization of the human egg. Before a woman even knows that she's pregnant, the environment that the developing embryo sees turns genes on, or off, or modifies the way they work. This continues through pregnancy and early childhood development and it's a process that's called epigenetic. It means that the genes of the developing baby and child are not changed in their basic DNA, but the way the genes work.

How they are transcribed to make proteins, that's how they're working, and that's changed. But we always thought that men just provided genetic material with sperm. A sperm was a sperm, and all it did was deliver a man's DNA to the egg. Now, in research that has been building up over the past several years, we are beginning to see the genes encoded in sperm can be modified by the environment in which they were developing, meaning, in the guy. And those modifications may affect the developing child.

Gene Modification

So let's start with mice. In 2013, in the Journal of Neuroscience, researchers reported that stressed mouse dads had changes in their sperm and their offspring had abnormal stress responses when compared to offspring of non-stressed mouse dads. It takes about 42 days to make a mouse sperm. During that time, the researchers exposed the mouse dads to be in one stressful thing each day. The smell of foxes, wet bedding, restriction in a tube for 15 minutes, new noises, that kind of stressful stuff. The sperm from the stressed mouse dads had the same DNA as the non-stressed dads, but the way the DNA was processed was different. And the mouse babies had abnormal stress responses as adult mice.

Well, what about human dads-to-be? The cord blood of babies of obese men was studied and they had changes in the way one of the genes that controls growth and calorie use was regulated. These changes were seen less in babies of normal weight men. These changes are associated with a tendency toward obesity in adulthood. Now, here's the cool part, this year researchers published a study of the sperm of obese men before and after they had weight loss surgery. They found different epigenetic patterns in the sperm in the men before they lost weight, compared to after they lost weight. Losing weight made a difference in the epigenetic programming of the sperm.

So what do we think we know? We know that we don't know about how large the effect of stress and obesity in a dad is on the baby and growing child and adult. We do know that there's evidence that a man's environment and behavior can change his sperm, and in the case of the mouse dad, not for the good of the mouse baby.

Pregnancy Tips for Men

So what should we do? We should tell men that are thinking of making a baby the same things we tell women. Clean up your act, eat well, maintain a healthy weight, try to manage your stress and response to stress. Consider yourself an equal partner in the health of your future child, literally. It takes 90 days to make a sperm so let's get cracking, plan ahead, it'll be good for you anyway, and thanks for joining us on The Scope.

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updated: May 8, 2018
originally published: January 12, 2016