И лишь небольшое колличество ученых

И лишь небольшое колличество ученых отводят решающую роль в развитии синдрома Каннера отводят внешним факторам ( неблагополучные семьи, воспитание в детском доме) 
Видимо, в развитии аутизма у детей принимают участие совокупность причин. 

Результаты (английский) 1:

And only a small number of scientists have a crucial role in the development of Kanner's syndrome take external factors (dysfunctional families, raised in an orphanage)
apparently in the development of autism in children are a set of causes. 

Результаты (английский) 2:

And only a small Number of scientists play a crucial role in the development of the syndrome Kanner assign external factors (dysfunctional families, at an orphanage) 
Apparently, in the development of autism in children are involved set of reasons. 

Результаты (английский) 3:

And only a few not logged scientists give a decisive role in the development acquired Каннера assign external factors ( disadvantaged families, education in the children's home)
apparently,In the autism spectrum disorders in children are involved the combination causes.