As part of a massive study that includes the contributions from scores of researchers across the globe, scientists have found a dozen genetic markers linked to fertility, offering hope to the more 
than 48 million couples worldwide who struggle to conceive.
Published today the research is the largest genetic epidemiological study on human reproduction ever done involving data from 62 studies. Those studies included information from 251,151 men and women regarding the age when they first had children, and another 343,072 men and women regarding the number of children they’ve had. All individuals were of European descent.
As modern couples increasingly wait until they are older to start families – which in and of itself can make it harder to conceive – the findings in this study may help couples determine how late is too late to have children, researchers said.
“One day it may be possible to use this information so doctors can answer the important question: “How late can you wait?” based on the DNA variants,” said Melinda Mills, the lead author of the paper and a professor at the University of Oxford. “It is important to put this into perspective, however, as having a child still strongly depends on many social and environmental factors that will always play a bigger role in whether or when we have babies.”
More To Come
This massive study, that included data collected over several years, illustrates the potential for research into fertility.
23andMe contributed a small part of data used in this study, but the work is an example of the potential for breakthroughs in research into the genetics involved in human reproduction.
Early in 2016, 23andMe began a collaboration with the personalized medicine company Celmatix focusing specifically on discovering genetic factors to dramatically improve the diagnosis and treatment of infertility.
You can read more about that collaboration here.
We expect to announce more on this promising collaboration in the near future.
Estimates are that between 10 and 15 percent of couples have trouble conceiving. Researchers said that the genetic markers identified in this study could potentially serve as drug targets for preventing or delaying age-related declines in fertility and sperm quality, or the markers might be useful for improving the outcomes in fertility treatments.
Led by scientists at Oxford University and University Medical Center Groningen in the Netherlands, the study focused on two common measures of reproduction – age of first birth and number of children born. What the researchers found were 12 genetic markers associated with reproduction, ten of those have never before been associated with fertility. In addition, many of the markers are in genes – or affect the expression of genes – involved in the development of reproductive organs or are tentatively linked to a variety of gynecological disorders. The two indicators for human reproduction used in this study – age of first birth and number of children ever born – have a strong relationship with fitness, human development, infertility and risk of neuropsychiatric disorders.
This gives scientists more insight into the underlying biology of infertility, researchers said. For example, one of the markers is linked to genes involved in sperm development and is also important in the development of ovaries, the uterus, and placenta.
The study authors point out that genetics is just one of many things that influence fertility in men and women. Personal choices, as well as cultural, economic and social environments also clearly play an important role. But the insights gained in this study could help what the researchers call “reproduction awareness,” a more grounded look at what is possible as couples wait longer and longer to have children.
23andMe principal scientist and statistical geneticist Dave Hinds, said the research is promising on many levels.
“Insights driven by this important research could help in treating the many couples who have difficulty conceiving a child,” he said.
And beyond these specific findings this kind of research is a good example of what else can be done, by combining genetic studies from around the world.
“It is why 23andMe is involved in this and other similar kinds of research. It’s another way to make the contributions from our own customers, who voluntarily participate in research, have an even greater impact in scientific discovery.”
The study appears in the journal Nature.