Question: My 3 years old kid plays games and visits YouTube for kids app on the mobile phone frequently. After some time some effort must be made to remove it from her. It seems like she is addicted to the phone. 

Apart from the personal experience, people around me also complain that using phone to play games and watch videos affects kids' mental health. 

What are the mental consequences using a mobile phone or tab to teach kids using video games or YouTube videos?

Answer: 
Although it is always wise to be cautious about the safety of your young child, in general it is developmentally normal and natural (and not at all sexual in the adult sense) for a three year old to touch or play with his private parts. It's generally a matter of curiosity, and perhaps increased access if he is recently out of diapers. Adult strong reactions to the behavior can reinforce it, as the child thinks, "There is something about doing this that attracts concern/interest from mom and dad!", which may make it extra interesting to do and watch how you respond.

A common way to deal with this behavior in a healthy way is to frame it as a matter of privacy, "It's okay to touch your private parts in private places, like in the bath; We don't touch our private parts in places like the dinner table or while visiting with relatives." You don't want to introduce a sense of shame; there is nothing wrong with a child engaging in this totally normal age-related behavior, but at 3 a child can begin to learn about boundaries and the appropriate time and place for doing things.

If, on the other hand, your child is showing other [troubling signs](https://rainn.org/articles/warning-signs-young-children), like overly sexual play with other children, sudden behavior regressions (like a loss of potty training), sudden excessive fearfulness or separation anxiety, or excessive knowledge of sexual topics, or tells you that they have been harmed by another person, then you should pursue the matter with professionals immediately.
I am the oldest of 5 children. My brother, the youngest, is 12 years younger than me, and uncircumcised.

Children learn the rules of hygiene from their parents and then tend to pass them obsessively to their younger siblings. My brother was constantly told not to play with his private parts by his four older siblings. 

Possibly as a result of this, when my brother was about 9, the doctor told my mother his foreskin was too tight! The doctor actually suggested that my mother manipulate his foreskin! She was uncomfortable with this, and it was agreed that my brother would manipulate his own private parts to loosen his foreskin.

In conclusion, children playing with their private parts is not only normal but may in fact be necessary for normal physical development.