In the entire world, Yafyasov (Yafyasov , Яфясов ) is an extremely rare unknown gender first name. Much more frequently, Yafyasov is the last name as well as the forename.
Яфиасов
Denis
, Яфясов 
) is an extremely rare unknown gender first name. Much more frequently, Yafyasov is the last name as well as the forename.