Can the way you were born affect your health? A new finding says it's possible that cesarean birth can change a baby's DNA compared with babies born vaginally.

We don't know if those differences are permanent but the study makes us want to take a closer look because one out of three babies in America is born by C-section and the rate is nearly half that in China. Some are for medical reasons but many are medically unjustifiable.

So far the procedure has been associated with increased rates of diseases such as type-1 diabetes and obesity. And the latest study shows epigenetic changes in the DNA of cesarean babies.

What is epigenetics? Basically it's when genes are turned on or off, sometimes due to environmental effects such as smoking. We now also know these changes can be passed on to newborns.

This change to the DNA occurs through a mechanism called DNA methylation. Cells use this mechanism to lock genes in an 'off' position when they no longer need it to express, for example stop new teeth growth. But this same mechanism can work against us when a gene that should be 'on' is switched 'off'.

In the new study with two groups of babies, one vaginally born and another through c-section, their stem cells were compared for DNA methylation. They found methylation changes in more than three hundred regions of the genome between the two groups, mostly in areas associated with the immune system. Again, we don't know if these methylation changes in the c-section babies are permanent.

The theory is that natural childbirth is stressful to the baby which could be an environmental signal to prep the baby for life outside the womb. A c-section baby would not experience that but it's early yet to declare they should.