IT'S the medical miracle that can become a nightmare. "Pregnancy reduction" -- as it's euphemistically called -- is a horrific decision for any would-be parent to have to confront.
It can go wrong and endanger the other foetus. And just how ethical is it to create a pregnancy and then decide to terminate it?
Irish couple Fiona Whyte and Sean Malone, who had twins using a surrogacy clinic in India, were the subject of an Irish Independent feature and an RTE documentary called 'Her Body, Our Baby' this week.
The documentary focused on what the couple called their "dilemma" of aborting one viable foetus with a heartbeat to allow the birth of their twins.
The Indian clinic's rules didn't allow for triplet surrogate births.
The thing is that reproductive medicine has now produced a paradox. We can now create life where it wasn't possible before -- but in doing this, doctors often generate more foetuses than they had intended.
A multiple pregnancy is liable to occur with fertility treatment and these kinds of pregnancies increase the risk of health problems for mothers and babies, including the possibility of premature births.
And so, after years of trying to conceive a baby, wondering if they would ever be able to have any children, some couples are finding themselves in this terrible situation.
Sometimes, after years of trying, you are finally pregnant but you're carrying so many foetuses that the odds are firmly stacked against them in terms of a whole range of possible disabilities and life-threatening risks.
Medical advice is in favour of terminating one or two of them. It became the norm in mega-pregnancies that all but two or three foetuses were terminated to lower the risks to the woman and to the foetuses.
The overwhelming majority of tweets in the aftermath of 'Her Body, Our Baby' documentary showed viewers were upset at what was very uncomfortable viewing.
One tweet read: "The fact that the surrogate was allowed to carry three embryos with the likelihood of one being 'reduced' is appalling."
Another said: "Horrible they're aborting the third foetus, imagine growing up & being told you were triplets but one was killed off."
A more positive reaction was: "Very Happy for couple who appear to be loving honest people but I'm uneasy about the ending of 1 life."
OVER the past decade, Irish fertility clinics have seen a significant increase in demand for their services, as women defer having babies until later, only to find that they are having problems conceiving naturally.
Up to 3,000 babies are born here each year as a result of IVF and other hi-tech interventions and between 20pc and 30pc of all IVF pregnancies result in multiple births.
Over the past 20 years, the twinning rate has increased very significantly -- from 11.7 in 1991 to a high of 18.0 in 2011.
We are about two decades into assisted reproduction in Ireland, yet there is no regulation for it.
The Irish Medical Council has set out the conditions under which it is ethical for a doctor to provide IVF treatment, but there is no legal framework within which fertility clinics can operate.
A Commission on Assisted Human Reproduction produced a report in 2005; in May 2005 the Minister for Health and Children referred the report to the Joint Committee on Health and Children for consideration but ever since, successive governments have not legislated for it.
We will never all be able to agree on the point that human life begins.
While one side will talk about preventing the birth of a severely disabled baby, the other side will call it murder.
If only one twin embryo is wanted, one doctor will talk about 'pregnancy reduction' or even selective survival and point to the medical danger involved in giving birth to multiple babies.
Opponents of this will call it the pursuit of designer babies, or feticide. These very real and difficult choices we all face. The very notion of a procedure that selectively eliminates some foetuses, letting others live, is little known and hasn't been debated.
Fiona and Sean's story was our reminder that scientific developments can lead to very painful choices.