Mice born from cloned sperm

Scientists from Cornell University's Weill Medical College in the US have announced that they have created healthy adult mice from embryos fertilised using cloned sperm. The 'pseudosperm' cells were cloned using a similar method to that used to produce Dolly the sheep. It is suggested that sperm cloning may help the one in 300 men in the UK with low sperm counts to become fathers.

Gianpiero Palermo, and his colleague Takumi Takeuchi, presented their findings at the annual conference of the European Society of Human Reproduction and Embryology last week. They detailed how they had inserted the heads of sperm into hollowed-out mouse eggs and initiated cell division by passing a small electric current through the egg. Using ICSI, a method employed in IVF, the scientists then used the cloned cells to create some 80 embryos, by using them to fertilise intact mouse eggs. Of the 13 mice that were born, four developed into adult animals.

The implantation of artificial human gametes is specifically prohibited under the draft Human Tissue and Embryos Bill and is also thought to be caught under existing UK legislation. If the Bill becomes law as it stands it would then require further legislation to permit cloned sperm to be used in fertility treatment. And before it can even be considered for use in humans, the technique needs to be further developed in the laboratory. 'We are a long way from the time when this will be able to be used in humans. There is much work still to be done to understand why impaired development and abnormalities in the embryo occur, and to take steps to avoid that occurrence,' said Takumi Takeuchi. In the meantime, the team say that studying cloned sperm could help shed light on some forms of male infertility. 'We can use the process to work out what exactly is wrong with the sperm', said Palermo.