After reading this article in New Scientist I'd have to say any intelligent design involved in humans was done by a alien mutant with an insane sense of humour who is now sitting in the middle of a galaxy far, far away and laughing his two of his three heads off.
Birds have better lungs. Our DNA makes mistakes all the time. Or genes don't last the distance. Our eyes are wired back to front so if we wanted great eyesight we'd have had to have been born a hawk.
The female Pelvis: Walking upright has made giving birth more dangerous for women than for any other primate.
Linear Chromosomes: The ends of linear chromosomes erode as cells divide, something that cannot happen with circular chromosomes.
External Testicles: In harm's way. I don't know about this. What's wrong with them being just a boot kick away from agony?
Vagina and Urethra near anus: Leaves women prone to genital and urinary infections. Going with the pelvis, I'd say the IDer was prone to misogyny.
Wisdom Teeth: Many of us have jaws that are too small for these third molars.
Mutant GLO gene: Like most primates, humans cannot make vitamin C, rendering us vulnerable to scurvy unless we get plenty in our diet.
The Appendix: No known function but if it gets infected it can kill you. Mine tried to kill me.
Windpipe next to the Gullet: Means choking is not uncommon. Even I have trouble swallowing, talking and breathing at the same time although I've tried.
Ulnar Nerve: Runs behind the elbow, where it is unprotected (think funny bone), instead of in front of it. There's nothing funny about getting whacked in the funny bone with a tree branch. I can testify to this.
Vulnerable Brain Cells: A few minutes of oxygen deprivation causes permanent brain damage in humans, yet an epaulette shark can survive for over an hour without oxygen. I reckon even the shark would have trouble surviving question time in Parliament.
Parasitic DNA: Our genome is littered with "jumping genes" that can cause genetic diseases.
Odontoid Process: This extension of the last neck vertebra can easily fracture and damage the brainstem.
Feet: After coming down from the trees, we ended up walking on the "wrists" of our lower limbs, leadin to all sorts of structural weaknesses. This one did tickle the funny bone.
The Y Chromosome: It is gathering mutations because it can't swap DNA with the X chromosome. In other words, men are on the way out and THE WOMEN WILL RULE, ahem.
Vulnerable Hearts: A little heart damage triggers a disastrous cascade of events that causes further damage. Like Dr. Who, we should have had a back-up pump.
And my all time favourite besides the kickable testicles,
Hairy Bottoms: Who needs them.
See what I mean about an insane sense of humour.
Any intelligent designer would have designed us with a self-destruct button if we even had one small thought of war or killing our own kind.