Father:  "Well, can your penis reach your asshole yet?"

Perplexed boy:  "No, I guess not."

Father:  "Well then, you're not yet ready."
 

One year after....
 

16 yr. old boy:  "Dad, I want to marry my girl."

Father:  "Well, did your dick reach your asshole yet?"

16 yr. old boy:  "Almost."

Father:  "Well, almost is not good enough."
 

Another year passed.....
 

17 year old boy:  "Dad, I really want to marry my girlfriend and now I'm capable."

Father:  "You mean your dick can already your asshole?"

17 year old boy:  "Yep.  You bet!"

Father:  "Then what the hell do you need to get married for?!"