According to a new research babies born by cesarean section are more susceptible to developing diseases including asthma and diabetes.
And scientists hold stress experienced by children during the operation responsible for making genetic changes that lead to the vulnerability, reports The Telegraph.
In the study, researchers found that the babies have important differences in their white blood cells, a crucial part of the immune system.
Prof Mikael Norman, a pediatric specialist, from the Karolinska Institute, in Stockholm, said: "Delivery by C-section has been associated with increased allergy, diabetes and leukemia risks.
"Although the underlying cause is unknown, our theory is that altered birth conditions could cause a genetic imprint in the immune cells that could play a role later in life."
He added: "When babies are delivered by C-section, they are unprepared for the birth and can become more stressed after delivery than before.
"This is different to a normal delivery, where the stress gradually builds up before the actual birth, helping the baby to start breathing and quickly adapt to the new environment outside the womb."
To reach the conclusion, the study looked at blood samples from 37 newborn infants, looking for differences in the make up of the DNA in their white blood cells.
The study has been published in the journal Acta Paediatrica.