Experts say it's probably only a matter of time before technology lets monkeys qualify as legal humans.

In a new article for journal Science, a pair of biomedical law experts say recent advances are beginning to "blur legal distinctions between human beings and other living organisms, between living human beings and dead ones, and between human tissues and cells and nonhuman ones".

Bartha Knoppers of the University of Montreal and Henry Greely of Stanford University say new practises like mixing human and non-human cells and grafting animal organs and tissue into humans, as well as new gene-editing technologies like CRISPR, mean it's time to redefine what a 'human' actually is.

"Against this movable feast of 'human' rights and biological developments, do the classical legal boundaries still matter, and if so, why? Altering the legal meaning of 'human' ultimately affects the foundation for all human rights."

Writing for site phys.org, science journalist Bob Yirka gave the example of a monkey implanted with human organs.

"Can it be argued that a monkey has the same legal rights as human beings if all of its organs (except, perhaps, its brain) have come from a human being?"