How many people have a living sister?
That question can't have an exact answer. Sorry but it's not possible to tell.
In general why most brothers' wives are more beautiful than husbands' sister- this is not my situation but I have noticed this many times with many people and most of the sister-in-laws?
Since most husband's sisters will eventually become some brother's wife, this "observation" is clearly nonsense.
Why adult sister sitting on brother's lap is looked as incest by some people even when it is done with innocent intent - Can't brother sister have some fun time and so what if they are adults?
ignore those people. They have filthy minds and enjoy thinking ill of others. Your family know what is right.
How many people living in US pay income tax?
Go to the IRS gov web site and use the search box for SOI Tax Stats - Individual Income Tax Returns Click on the below Related Link