Hi I Am A 31 Year Old Who Has A

hi I am a 31 year old who has a 6 year old child and is now trying for the second. my boyfriend is 32 and is trying for his first. its been a year now and we are unsuccessful in becoming pregnant. I have no known illnesses but at age 15 he (my boyfriend) had a surgery done to untwist his testicles . could this be a reason why we not able to become pregnant?