An IVF technique which lets eggs develop in the womb rather than the test-tube straight after fertilisation is to be trialled in the UK.
Could the womb produce better quality embryos than the test-tube?
Researchers hope that the natural environment of the womb will help produce stronger embryos.
At present, an embryo is transferred to the womb after a few days growing in special liquid in a laboratory.
But this new technique would see fertilised eggs placed in a device which is then planted in the womb.
After a few days the device is taken out and the embryo deemed to have the best chances of survival reimplanted.
Initial, anecdotal evidence from pilots in Belgium suggests the embryos produced in vivo rather than in vitro are of a higher quality - and therefore have a better chance of survival.
In addition to establishing whether the technique improves the chances of pregnancy, researchers are also keen to find out whether these embryos have fewer chromosomal abnormalities - which can lead to conditions such as Down's Syndrome.
"We have often wondered whether the rate of abnormality is higher with in vitro embryos, but we have never been able to establish this," says Dr Simon Fishel, head of the Care Fertility group of clinics which is carrying out the study.
"Hopefully this trial will at least provide a partial answer."
The group is recruiting 40 women under the age of 37 to take part in the trial, which will be carried out in Nottingham.
There is currently intense interest in developing new techniques which produce better quality embryos, and thus minimise the need for several embryos to be transferred to the womb in the hope that one will survive.
This technique is producing large numbers of multiple births, which can put the lives of both mother and baby at risk.
Reproductive specialists were cautious about the trial.
"It's an interesting idea, but it's not entirely clear what they are trying to do," says Professor Adam Balen of the British Fertility Society.
"Even in natural conceptions the eggs do not spend those first days in the womb, but in the fallopian tubes.
"I'd like to see a bit more science before I got too excited about this."
Richard Kennedy of the Centre for Reproductive Medicine in Coventry agreed.
"Of course the more you can circumvent artificial systems the better, but one of my concerns about this would be that you have to put it in, remove it, before then putting it in again. "
Care Fertility says it hopes to have an initial results by May or June, and a clearer picture of how successful the technique is by the end of year.