My 2 yr olds check up they said one of his testicle is not dropped, he has been grabbing them crying. his father had a herniated testie. genetic?

No, but needs care: Some aspects can be genetic, but an undescended testicle needs attention at this age. It is common for babies to have retractile testicles, that usually resolve. If one is truly not descended, it needs to be found and surgically addressed.

Should get re-eval: Undescended testicle poses higher risk of developing testicular cancer and so surgical intervention is likely needed. At two yrs and it has not descended likely means it won't. This typically does not cause pain and so if he is crying, it maybe something else such as urinary tract infection--it burns when he pees. I suggest get him evaluated asap. Good luck.