Some people claim that living organisms, in particular humans, are proof of “intelligent design”. Granted, living organisms have a very complex structure, but some aspects of their structures argue against intelligent design. Looking at the human body, we find

1. a tail bone – the coccyx is clearly a remnant of a tail that humans once had. In very rare instances, about two dozen since 1900, individuals were born with six-inch tails. Clearly, genes exist to produce tails, but they are suppressed during normal development.

2. nipples – all males have two nipples, which have no function whatsoever. On rare occasion, males develop breasts, so it is clear that genes exist in the bodies of males to produce breasts, but they are suppressed.

3. toe nails – these structures have no function.

4. bodily hair – human hair is vestigial, and serves no function. Based on embryonic development, humans were once covered with hair, as the lunago proves, but the growth of body hair is largely suppressed, although the extent of that suppression varies.

5. retinal position – in the human eye, the path of light traverses the retina, and is reflected back to the active side of the retina. The rods and cones of the retina actually face away from incoming light.

6. external ears – these appendages have no function, but have a complement of muscles and nerves which were used to move them but are now vestigial. The muscles are complete with nerves and blood vessels.

7. menstruation – only human females exhibit this phenomenon where by once per month the uterine lining is shed with an accompanying blood loss.

8. voluminous sperm production – an ejaculation contains millions of sperm, only one of which will fertilize an ovum; the others die.

9. size of female breasts – only human females have greatly enlarged breasts which they retain all of their lives, even after menopause. Breast sizes vary widely, and their size is unrelated to lactation.

10. path of the large intestine – the large intestine is located below and away from the anus, meaning that undigested food must be pushed across the abdomen, upwards in the abdominal cavity, again across the abdomen, and then curve back to the anus

11. trachea position – the trachea and the esophagus cross over each other, instead of having separate paths. When a person swallows food or liquids, a flap of cartilage, called the epiglottis, is activated by nerve impulse, and it covers the opening to the trachea.

12. spinal curvature – due to our upright posture, the spine is twice curved, and the pressure on the lumbar vertebrae often causes severe back problems.

13. ovum capacity – a human female is capable of producing about 250,000 ova, whereas, over her reproductive span, only about 500 are released, and, if she became pregnant each year during her reproductive years, fewer than 80 would be fertilized.

14. descent of male testicles – the testicles are formed inside the body cavity, and descend through it, leaving weak areas in the abdominal wall leading to hernias

15. wisdom teeth – generally regarded as useless teeth, several groups of humans are born without them

16. cremasteric system – nerves along the inner thigh of males stimulate contractions in the cremasteric muscles which pull the scrotum towards the body; the minute withdrawal of the scrotum has no function.

17. erector pili muscles – tiny muscles in the skin which cause “goose bumps”; perhaps they had a function in the past, but they are now useless.

18. pathways – nerves and blood vessels traverse twisted paths instead of more direct ones

19. organ support – the manner in which our internal organs are supported is best explained by a horizontal, not vertical, posture.

20. remnant structure – the human eye has a remnant of a structure called the nictating membrane, which has no function in humans