bringing forth

I ever remembered a girlfriend showing me the picture of her then-current boyfriend on MSN, the Mother of all online chat engines.
I said He's good looking!
She said Thank you! =)

It is just three degrees more silly and illogical than replies to compliments on looks:
(any letter from)A-Z says You're pretty/cute/good looking etc.!
You say Oh thank you! =)

Of course you could be a really good dresser; or much better still, a character with a generous dose of confidence and assuredness to boot. But in all honesty you cannot possibly say thanks to what is certainly a blessing of admirable genes from those who have come and gone before you? ie. your parents' parents' parents' to the power of (any letter from)A-Z?

So are you thanking us for acknowledging your good taste in choosing a mate; sharing your appreciation for looks he did not fully earn on his own efforts; or rejoicing over the possibility that if all works out well, you will be able to partake in the double joy of blessing a future generation with admirable genes?

If I were your progeny, I'd say thanks to that!