Too Much Sunlight May Cause Lower Fertility Levels Over Generations

Most people know that too much sunlight can cause skin cancer, but did you know it may also cause problems in fertility? Scientists have found that increased UV radiation can have an effect on human fertility over generations.

In order to better understand how the sun's rays might affect humans, the researchers studied church records from 1750 to 1900 and looked at life history variables, such as how old women were when they had their first child and last, how many years passed between the birth of each, how many of these children survived and how many of these children were married and had children of their own.

The researchers then took this information and compared it with environmental factors, including solar activity. Surprisingly, the scientists found that children born in years with lots of solar activity had a higher probability of dying compared to children who were born in years with less solar activity.

In fact, the lifespan of children born in years that had a great deal of solar activity was 5.2 years shorter than other children. The largest difference was in the probability of dying during the first two years of life. In addition, children born in years with high solar activity and who survived were more likely to have fewer children who, in turn, gave birth to fewer children than others.

UV radiation can have a positive effect on human vitamin D levels. That said, it can also have a negative impact of vitamin B9, also known as folate. Previous studies have shown that low folate levels during pregnancy are linked to higher child mortality.

"There are probably many factors that come into play, but we have measured a long-term effect over generations," said Gine Roll Skjaervo, one of the researchers, in a news release. "The conclusion of our study is that you should not sunbathe if you are pregnant and want to have a lot of grandchildren."

The findings reveal that an excess of sun may be bad for you if you're looking to have a child. That said, further research is needed before any firm conclusions are drawn.

The findings are published in the journal Proceedings of the Royal Society B: Biological Sciences.

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