Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

The Joke

The comic features a conversation between a human man and a large blue genie-like figure who appears to be God or a divine creator. The man is complaining about the design of the human body. He points out flaws: the body has poor sanitation (waste elimination) next to reproduction, the design choices seem arbitrary and clumsy. The blue figure (representing natural selection or a creator) gets increasingly defensive and flustered as the man critiques specific anatomical design choices.

The man asks where they would put various body parts, and the creator struggles to justify decisions like having an open body cavity, running tubes through exposed areas, and other questionable anatomical arrangements. When the creator snaps "Natural selection is a tinkerer, not an idiot!" and then immediately apologizes, the man says he has some questions about fingers. The creator excuses himself, saying he needs "to go yell at a guy about male nipples."

The Humor

The comic personifies natural selection (or evolution) as a harried, defensive designer who knows the human body is full of compromises and poor design choices but gets irritated when they are pointed out. The humor comes from treating evolution as if it were an intelligent designer who should be held accountable for anatomical oddities -- the proximity of waste and reproductive systems, the vulnerability of exposed organs, and vestigial features like male nipples. The final punchline about male nipples (which serve no functional purpose in males) is the creator fleeing to deal with yet another design complaint, suggesting an endless backlog of angry customers.

References

The comic references the argument from poor design (also called dysteleology), which notes that many biological structures are poorly "designed" from an engineering standpoint -- evidence that they are products of evolution's incremental tinkering rather than intentional planning. Male nipples are a classic example: they exist because the basic body plan is established before sexual differentiation in embryonic development.