A giant panda in Berlin's zoo might finally conceive if Chinese experts' efforts bear fruit. Six earlier attempts to impregnate 19-year-old Yan Yan with sperm from her Berlin zoo companion, Bao Bao, 26, have failed. As a last resort, scientists are now trying to artificially inseminate the animal with a cocktail of sperms from several pandas in China.

Experts from Beijing have assessed Chinese-born Yan Yan's suitability for the project. But the panda's veterinary doctor fears that creating the right conditions for artificial insemination might not be such an easy task.

Pandas are fertile only once a year for 36 hours. Their hormone levels also have to be taken into account. This method has been successful in Beijing where the Giant Panda Research Centre used sperm cocktails to breed 64 cubs.