A fertility expert claims to have implanted cloned human embryos into the wombs of several women with the intention of producing live offspring.

Operating from a secret laboratory thought to be somewhere in the Middle-East, Dr Panayiotis Zavos also claims to have created clones of several dead people, including a 10 month old baby killed in a car accident - not for implantation but for the purposes of study. None of the implanted embryos, created in a similar way to Dolly the sheep, produced viable pregnancies.

Scientists disputed Dr Zavos's claims, which are supported by an independent documentary maker. Lord Robert Winston of Imperial College London dismissed the claims as 'yet another one of his claims to get repeated publicity'. Studies in other species, including primates, suggest that producing live births is potentially feasible but difficult to achieve, and associated with major safety and ethical concerns; these concerns have also been expressed by scientists.

In the UK the Human Fertilisation and Embryology Act (2008) allows the creation of cloned embryos for therapeutic and research purposes only, not for the transfer into a woman's womb; such reproductive cloning remains illegal in most countries. Dr Zavos's scientifically unsubstantiated claims may well prove to be a hoax but are a reminder that there remain individuals determined to break one of the greatest 'ethical taboos' in biology. (independent.co.uk 2009; 22 April, guardian.co.uk 2009; 22 April)