Pleasures of which I am guilty.

Lucifer is the name of the archangel cast into hell -- theologians disagree on whether he and Satan are separate beings -- and as such has long been on the forbidden list for religious parents. Still banned in New Zealand, Lucifer is occasionally used in the contemporary U.S.: Six boys were given the name in the most recent year counted.

Unlike Pearl and Ruby, this is one gem name suited for boys, the final x making it sound strong and virile. Musician Iggy Azalea chose the name Onyx for her son.

Asking for trouble. Rebel Wilson is female, but this name is truly gender neutral, though hardly neutral in any other way. Rebel is undoubtedly one of the edgiest boys' names starting with the letter R.

Even less subtle than Duke or Earl, this name shot up the popularity charts in 2013, the same year young Prince George was born and the craze for all things royal (and Royal) began. Today, it's a leading boys' name on Nameberry's own popularity charts.

A short form of the Biblical name Reuben and especially its streamlined form Ruben. As a gemstone name, it's currently enjoying a fresh boom of popularity for girls – nearing the US Top 50 for the first time in almost a century.