I know, I know, I'm not native Chinese! I'll toss this into the answer pile and then move on!
I've started to study Buddhism (and it is very confusing to me!), but from what I have read and asked of people, Guanyin started as male and to some, is still considered to be male. However, Guanyin has been revised to be female and is considered by most to be female.
(This is only one of the reasons I find Buddhism to be confusing! I also find it quite difficult to keep up with all the Bodhisattvas!)
Here's a brief history:
Guanyin, the goddess of mercy
Bodhisattvas are enlightened beings who have put off entering paradise in order to help others attain enlightenment. There are many different Bodhisattvas, but the most famous in China is Avalokitesvara, known in Chinese as Guanyin.
Bodhisattva Avalokitesvara was depicted in the male form in the beginning. But later on the image became that of either a man or a woman, and eventually, since the Yuan Dynasty, the image gradually became predominantly that of a young woman, such as one holding a holy vase in her hand, pouring out holy water to save the multitude. Some people even call her the Goddess of Mercy or the Female Buddha.
According to legend, Guanyin was born on the nineteenth of the second lunar month, achieved enlightenment on the nineteenth of the sixth lunar month and achieved nirvana on the nineteenth of the ninth lunar month. It is said that she is the top Bodhisattva beside Shakyamuni Buddha, and an assistant Bodhisattva beside Amitabha Buddha in the Western World of Ultimate Bliss. It is believed that any sentient being who recites her name during a disaster would be heard and salvaged by her, which can explain why she is the most worshipped figure in Buddhism in China. Literally in the Chinese language, "Guanyin" means "observing the sounds", which means Guanyin would always observe all the sounds from the world and always listen to requests from her worshippers.
http://www.bergerfoundation.ch/more/Guanyin.html
(Now you've got me really curious, though! I've plugged this into my "dig deeper file" when I have more spare time . . . rolling eyes!)
EDIT: Have you tried going down to one of the temples in your town and talking to the monks? They would probably be the most informed on the topic and would be a wealth of information. I'm hoping to do the same (talk to monks at temples about a variety of topics) at some point, but I need to know some more specific vocabulary first.