New mothers should not embrace the trend of "seeding" their babies with vaginal bacteria, say doctors, according to BBC.It exposes children born by Caesarean section to bacteria that could have coated their bodies if they had been born vaginally. The idea is bacteria help train the immune system and lower the risk of allergies and asthma. But doctors in Denmark and the UK said there was too little evidence and it may be doing more harm than good. Being born by Caesarean section is linked to a higher risk of some immune-based diseases. And there is growing medical interest in the role of the microbiome - the micro-organisms that call our bodies home - in preventing disease.