If you are a hard gainer, take a good look at your C. GENETIC ENDOWMENT.
Genetic endowment constitute the things that are passed down from parents and ancestors. These things can be physical characteristics or hereditary health issues. Hereditary issues like allergies or other diseases can be passed down from generation to generation.
Hard gainer is a person who practices body building but finds it challenging to develop musculature regardless of the amount of effort put in. It is often associated with the ectomorph body somatotype.
Ectomorphic somatotype is characterized by linear, thin, usually tall, fragile, lighly muscled, flat chested and delicate physical and psychological trains inherited from parents or ancestors.