Genma Saotome is Ranma Saotome's father and the sensei of the Saotome Dojo of Musabetsu Kakutō Ryū karate ("School of Indiscriminate Grappling," more commonly known in the West as "Anything Goes Martial Arts"). During the time when Genma took Ranma on a decade-long training voyage to improve their martial arts skills, he insisted on going to Jusenkyo in China - a place which he believed to be a training ground. However, because of Genma's ignorance of the Chinese language, he did not realize that the ground was unfrequented because it was cursed. Genma realized all too late the mistake he made, after his son knocked him into a cursed spring during this fateful training session.

Genma was knocked into Shonmaoniichuan (熊猫溺泉 Xióngmāoníquán), the Spring of Drowned Panda. Due to the nature of the Jusenkyo curse, a victim who falls into the spring is cursed to turn into who or whatever drowned there when doused with cold water. Thus, whenever Genma is splashed with cold water, he becomes a giant panda. Hot water, as with the rest of the Jusenkyo-cursed characters, can change him back into human form.

Despite the fact that he and his son were cursed, Genma still brought Ranma back to Japan to fulfill a marriage engagement with his longtime friend and fellow martial artist Soun Tendo, the terms of which were as follows: Ranma would marry one of Soun's daughters and carry on the Anything Goes School of Martial Arts.

Genma and Soun decided that Soun's youngest daughter Akane would one day marry Ranma after Akane's sisters made the ruling on their own—against their will, at least at first. Genma currently resides in the Tendo Dojo along with Ranma, in the hopes that one day Ranma and Akane will get married and fulfill the agreement made by the two families. He spends most of his time playing Go or Shogi with Soun, although he briefly had a job at Dr. Tofu's clinic.

Unlike Ryoga, Mousse and Shampoo, Genma automatically regains his clothing when shifting back to normal, despite being too large to keep them in cursed form. The only other characters who shares a similar trait is Pantyhose Taro. Occasionally, primarily in the earliest stories, the top half of Genma's gi and his glasses will also remain on him when he turns into a panda.

(Source: Wikipedia)