Why does cilantro taste like soap to some people?

Cilantro, also called coriander, contains aldehyde compounds that are also found in soaps and lotions. A 2012 genetic study of about 25,000 people found that a variant near the OR6A2 gene, which codes for a smell receptor tuned to aldehydes, was linked to disliking the herb. Another study found the soapy perception varies by ancestry, reported by roughly 21 percent of East Asians and 17 percent of people of European descent, but only a few percent of people of Middle Eastern or Hispanic heritage. Because taste depends heavily on smell, the soapy aroma dominates the flavour for these people. Crushing or cooking the leaves breaks down some aldehydes and can make cilantro more tolerable.