Scurvy is a disease that most animals cannot catch. It's caused by a nutritional deficiency of ascorbic acid (aka Vitamin C). Other animals, besides primates, can make their own ascorbic acid within their own bodies using only glucose, because they have a particular gene which codes for an enzyme called L-gulonolactone oxidase.

This gene can also be found in the human genome, except that it's broken, and doesn't code for anything. It's not even parsed when assembling proteins in the cell.

Consult image:
http://img9.imageshack.us/img9/7052/gulo.png

If you believe that your god created humanity, how do you justify the fact that the human genome contains a broken copy of the gene we'd need to avoid catching scurvy, and which most other mammals possess a working copy of? Why would your god deny humans resistance to a disease that almost all other animals are resistant to?

If you believe it is because of sin, then why do even people who have been absolved of all sin have this genetic deficiency, PLUS then who do some non-humans have the same deficiency when only humans can sin?