When Louise Brown was born in 1978, she became the first baby conceived outside the womb, often referred to as a "test-tube" baby.
Now, 34 years later, fertility experts estimate that 5 million children around the world have been the result of their parents using assisted reproductive technologies.
The International Committee for Monitoring Assisted Reproductive Technologies, an independent, international non-profit organization that collects and disseminates world data, presented their estimates of successful births resulting from IVF and ICSI treatments at the 28th annual meeting of ESHRE, the European Society of Human Reproduction and Embryology, on Sunday.
They based their 5 million estimate on "the number of IVF and ICSI treatment cycles recorded worldwide up to 2008 with estimations added for the following three years," according to an ESHRE press release. The release goes on to say that the cumulative total of births was put at 4.6 million for last year, and that this year it will reach about 5 million.
IVF, which stands for in-vitro fertilization, is a procedure where a woman's eggs are fertilized outside her body. The eggs are removed from her ovaries and then placed in a petri dish with sperm for fertilization to occur.
To improve the chance of fertilization of actually occurring, doctors may choose to inject the sperm directly into the unfertilized egg - an IVF procedure that is called intracytoplasmic sperm injection.
According to the National Institutes of Health, "many fertility programs routinely do ICSI on some of the eggs even if everything is normal."
Once the fertilized egg starts dividing, it's considered to be an embryo. After a few days of dividing in the lab (usually 3 to 5), the fertilized egg can either be transferred to a woman's uterus or frozen and transplanted at a later date.
The ESHRE statement also says that data collected by ICMART suggests there are around 1.5 million ART cycles now performed around the world each year, producing approximately 350,000 babies. It goes on to say that the United States and Japan are the most "active" in performing assisted reproductive procedures, but that Europe is by far the most active region in the world.
IVF procedures are no longer considered experimental, but they are also not entirely risk free. In some rare situations, fertility drugs lead to a woman's ovaries being overstimulated, resulting in a build up of fluid in her abdomen and chest. When the eggs are retrieved from the ovaries women are put under anesthesia, which poses a risk of having reaction to the anesthesia drug. Since this is a surgical procedure, there's also the risk of bleeding, infection and damage to surrounding areas.
Also, if multiple embryos are transferred into the uterus and continue into a full pregnancy, the mother and unborn children are at greater health risks than mothers carrying a single fetus.
However, a study published in the New England Journal of Medicine last week found that under the right circumstances, IVF pregnancies can be just as successful (leading to the live birth of a child) as naturally conceived pregnancies.
The cost of the procedure can be prohibitive for many couples. While some health insurance plans in the United States pay for IVF treatments, others do not. And the costs can vary depending on where you get the procedure done. The NIH estimates the IVF treatment may cost anywhere from $12,000 to $17,000.
"Five million babies are a clear demonstration that IVF and ICSI are now an essential part of normalized and standardized clinical therapies for the treatment of infertile couples," said ESHR chariman Dr Anna Veiga in the statement. "Many aspects have changed since the early days of IVF, especially the results in terms of babies born, but there is still room for improvement."