The distinction between organic and inorganic carbon compounds, while useful in organizing the vast subject of chemistry... is somewhat arbitrary. Organic chemistry is the science concerned with all aspects of organic compounds. Organic synthesis is the methodology of their preparation.
No, it is not possible to contract the typical STDs, such as syphilis, gonorrhea, chlamydia, hepatitis B, etc. from wearing someone else's dirty underwear. However crabs and scabies, may be spread in this fashion.
There is some debate among researchers as to whether or not boxers or briefs are best for male fertility, but the consensus is that tighter more restrictive styles of underwear slightly reduce the number of healthy sperm that a man produces â though, not by very much.