TweetJust a theory:
It "could be due" to the fact that your father's natural test production is quite a bit lower at his age therefor he will respond better to exogenous test than you who probzably (at your age) still has a pretty normal test profile.
Kind of like:
Who's going to respond more to Cardio?:
1) a 300 pound fat-ass who's not used to exercise
OR
2) an in-shape bro trying to loose that last 3 pounds!