It's possible men who exercise regularly could alter the genetic composition of their brain and sperm, leading to them having smarter babies than those men who don't exercise.
Researchers at the German Center for Neurodegenerative Diseases were keen to find out if exercise impacted the brains and sperm of male animals, in turn benefiting their offspring.
It's already accepted that exercise and lifestyle choices boosts brain activity, but what isn't clear is how that impacts future generations. So, researchers tested the theory on mice.
Half the mice did no exercise and the other half were put into cages with running wheels and toys to encourage physical activity and stimulate their brains (also known as environmental enrichment or EE).
After 10 weeks, they tested the mice and found the active mice to have stronger neuronal connections than their inactive peers. They also performed better on cognitive tests.
Then when they mated with female mice (that had not been actively exercising) some of their offspring also had stronger neuronal connections than the babies born to two inactive parents. The baby mice learned faster and remembered more things than their peers.
The researchers then analysed the paternal sperm and found changes in its composition indicating that exercise had impacted positively on its genetic make-up.
Senior author of the study, which was published in Cell Reports, Professor André Fischer, said the findings suggest that activity in one generation can impact on the following generation. And while this study was done on mice, they are now planning on doing a similar study on men who exercise.
"The idea that EE training in adulthood provides a cognitive benefit not only to the individual undergoing this procedure, but also to its offspring, is fascinating," Professor Fischer said.
"Whether these findings are translatable to humans needs to be determined."
Sam Wood, fitness expert and creator of 28 by Sam, said while the study was "interesting" it was still early days.
"Not sure about it being proven just yet, but I'm definitely in the camp that exercise is beneficial and can only help the health of you and your child," he said.
He doubts exercising when trying to conceive makes your baby "smarter", but "it can't hurt".
Wood and his fiancé Snezana met on the Bachelor in 2015 and welcomed baby Willow into the world in October 2017. The couple are super fit so it goes without saying that she would be one of the smartest babies in the world, wouldn't she?
"It's amazing how biased you become as a new parent, so proud of the littlest things like rolling over or understanding peek-a-boo," Wood said.
"As I'm sure every parent says, we do have the most perfect baby in the world."
Regardless of the findings he said it was "very important" dads, including him, did all they could to get, and keep, fit.
"Babies are lots of work and being fit, healthy and alert has never felt so important," he said.
"From functioning on a little sleep and carrying Willow for hours when she falls asleep right through to even thinking about how I now want to live for as long as possible to spend as much time as is humanly possible with my children.
"It really does change your perspective and sharpen your focus."