Can you imagine amputating a perfectly healthy limb?

For most people, the thought of doing that is unthinkable, but for some it feels absolutely normal.

They suffer from a very rare condition called body integrity identity disorder or BIID. It’s a psychological condition in which a person has the uncontrollable desire to electively amputate a limb. People with this disorder often feel one of their limbs is truly not their own.

Dr. Christopher Ryan, a psychiatrist at the University of Sydney in Australia, said people suffering from this disorder should be able to opt for amputation, the Australian Associated Press reported Thursday.

"I am not saying we should unthinkingly cut off people's legs," Ryan told the news agency. "I realize that the idea strikes almost everyone as lunatic when they first hear it. However, there are a small number of people who see themselves, and have always seen themselves, as amputees," he said.

The disorder made headlines in 2000 when a surgeon in Scotland amputated a healthy leg from two patients with the disorder, according to the report.

Click here to read more on this story from AAP.