Yes, very likely.
The scientific explanation is that your body gets exposed to allergens when young and learns that there is not a huge response required, so the body learns how to handle it. When they see the same allergens later, it is not a problem.
Now, disinfect everything and prevent your baby getting exposed to these things early on, and they get exposed to them later and have a huge response.
Sure, some bacteria may protect against some things, but explain why we seem to have HUGE increases in allergic reactions to things at a time when people are trying to be super clean by disinfecting everything?
I saw a program on Insight where this Malaysian couple were trying to explain to their relatives why their child had an allergy to peanuts which was absolutely unheard of in their family, and the only difference was probably that the Australian based couple were keeping things superclean.