The word bitter can make some of us wince. In conversation, we talk of "a bitter pill to swallow" or "bittersweet" memories.
But if you're puzzled by the bad emotional rap on bitter — perhaps you even like the taste of bitter greens or bitter beer — it may say something about your genes.
Scientists have been studying a particular taste receptor gene to understand why some of us may be more predisposed to liking bitter foods and hoppy beers.