Beyonce and Jay-Z are never far from the headlines. This summer they've been making legal news by applying to trademark the names of their newborn twins, Sir Carter and Rumi Carter.

It's not the first such effort for the couple, Beyonce Giselle Knowles-Carter and Shawn Carter, and their company BGK Trademark Holdings, which is represented by Latham & Watkins counsel Jonathan West. BGK trademarked “Blue Ivy Carter,” the name of their first child, in 2013 but later abandoned the mark. The couple's new application this year has run into opposition from an existing company called Blue Ivy.

We spoke with Knobbe Martens partner Ian Gillies, a former professional musician who now practices IP law, about why celebrities would trademark their children's names, and the trademark lessons for everyday clients.