U need good diet . more than genetic it's lifestyle also.so have healthy diet. I can help with 4-5 KGS muscle gain in month

Hello.......if there is any medical problem with you like thyroid disorder or worm infestation or GIT problem you don't gain weight.. If you are healthy and active ,you should gain... Have more of milk and milk products, fruita and vegetables.. If your non vegetarian have egg, meat... Do exercise like jogging, yoga, maintaining body fitness is very important.