Ranma Saotome

Ranma, the only son of Genma and Nodoka Saotome, was taken from his home by his father when approximately 2 years old, to begin a 13-14-year training trip to perfect his skills in the martial arts.

While he was still a child, he befriended Ukyo Kuonji, the daughter of a travelling okonomiyaki chef and martial artist, although he was unaware that she was a girl. Genma engaged Ranma to Ukyo in exchange for her father's food cart, but he abandoned Ukyo and ran off with the cart without ever telling Ranma about the engagement or correcting him about Ukyo's real gender.

Later, near the end of the trip, Genma took Ranma to a training ground in China named Jusenkyo that few people used, due to the springs being cursed. Falling into them would transform a person into whatever first fell in. Not knowing this, and not having the patience to listen to a warning from the local guide, Genma attempted to train with Ranma atop the bamboo poles which jutted up out of the pools. When Ranma knocked Genma into Shonmaoniichuan/"Spring of 'Drowned' Panda", he was surprised to watch a panda emerge from the pond and leap onto one of the poles. Genma, now cursed, was able to hit a surprised Ranma into Nyannichuan (Niángníquán), or the "Spring of 'Drowned' Girl". Thus he turns into a female version of his original form when splashed with cold water, which is only (temporarily) reversible through contact with hot water.

By : Wikipedia.com