A new study claims that kids who are brought up in very large families, tend to develop behavioural issues and also develop their cognitive faculties slower.
The study further claims that when the family size is too big, parental attention may decrease and this might result in poor performance of kids in cognitive abilities test.
This study also says that these effects are not to be taken easily as they persist all through the childhood of the baby.
Also, as childhood tends to impact kids a lot, parents need to take special care about the parenting methods they choose and the time they spend with children.
Maybe, there could be advantages of joint family. But if children are not given enough attention then it could cause several other problems as neglected children tend to experience several issues which might not come to the attention of the parents.
So, maybe these days are more suited for nuclear families. But still, it doesn't mean that kids tend to grow healthier in nuclear families too because the main issue of concern here is parental attention. If enough parental attention isn't there, any environment could be a bad environment for raising kids.