Why does asparagus make your urine smell strangely?

Breakdown compounds.: The metabolism of certain compounds in asparagus leads to excretion of methanethiol, dimethyl sulphide, methyl mercaptan, & asparagusic acid that causes the characteristic odor. The onset of the odor is rapid, often 15-30 minutes after ingestion. There a appears to a be genetic component in the ability to smell the odor, and a candidate snp was identified in a 2010 genome association study.