Okay.... Just to bring some kind of positive informational aspects to this.... "ninja stars" is just a common colloquialism (mainly due to the so-called "ninja boom" of the early 80's and associated media) for what are known in Japan as Shaken (pretty literally "wheel blades"), or Hira Shuriken ("flat side-handed blades"). They are a subset of shuriken, which is really almost any kind of projectile blade... although they can also be used as a hand-held in close weapon, the basic usage and predominant characteristic of a shuriken is that it is a thrown blade. Over the centuries, there have been almost innumerable different shapes and designs of shuriken, from simple spikes and needles, to specifically crafted tapered shapes, to double ended, to ones shaped like knife blades, as well as the iconic star-shaped designs... which include three, four, five, six, eight, ten, twelve pointed designs... some of which are collapsable, others made with two spike-style (bo-shuriken) joined together, as well as specific designs such as Manji-shuriken ("flowing point"... either curved, or basically swastika shaped), ones with seeming "handles" (Araki-ryu shuriken, featuring an elongates spike among the other ones), and more. Shuriken have been a part of Japanese arts for centuries, and have been (and continue to be) taught in many arts, such as Tenshinsho Den Katori Shinto Ryu, Takenouchi Ryu, Araki Ryu, Kukishin Ryu (Kukamishin Ryu now), Takagi Ryu, Namba Ippo Ryu, Negishi Ryu (a shuriken school itself, with little else to the syllabus), Shirai Ryu (no longer extant, it's methods have been subsumed into Negishi Ryu), Kiraku Ryu, Yagyu Shingan Ryu, Yagyu Shinkage Ryu (there is a famous type of shaken known as a Yagyu shuriken, for instance... "star-shaped" blades were not really "ninja" in anything other than the movies), Kobori Ryu (five and eight pointed items), Chushin Ryu, Enmei Ryu (an early version of Musashi's Hyoho Niten Ichi Ryu), Tsutsumi Hozan Ryu, forms of Itto Ryu, and many others... in fact, most sword schools would typically have at least some teachings for throwing blades. In recent times, the Meifu Shinkage Ryu was created by Someya Chikatoshi in the 1970's, based in his training in Katori Shinto Ryu under Sugino Yoshio-sensei, and his further experimentation with various shuriken types and methods. Today, the school is under it's second headmaster, Otsuka Yasuyuki, is keeping the tradition of shuriken going. So, in answer to the OP... yes.