Sonnet 12 - William Shakespeare

This is a rather...unusual "carpe diem" poem!  Definitely not my idea of a romantic plea for favor; I wonder if he meant it to be humorous.  The conclusion certainly strikes me as almost ridiculous!  (Note that "breed" in the last line is used as a noun, meaning "progeny".)

Sonnet 12

When I do count the clock that tells the time,
And see the brave day sunk in hideous night;
When I behold the violet past prime,
And sable curls all silvered o'er with white;
When lofty trees I see barren of leaves,
Which erst from heat did canopy the herd,
And summer's green all girded up in sheaves,
Borne on the bier with white and bristly beard,
Then of thy beauty do I question make,
That thou among the wastes of time must go,
Since sweets and beauties do themselves forsake
And die as fast as they see others grow;
   And nothing 'gainst Time's scythe can make defense
   Save breed, to brave him when he takes thee hence.