The Women’s Tennis Association (WTA) this week announced a landmark policy that will allow female tennis players to take time off to freeze their eggs or embryos without jeopardizing their professional rankings. Women ranked in the top 750 who miss over 10 weeks of competition can now use a special protected ranking to enter up to three tournaments within 10 weeks of returning. Former US Open champion Sloane Stephens, who froze her eggs in the off-season, said the move was “the best thing possible”.

This policy is part of a broader and necessary conversation about the importance of fertility planning for women in general, and especially for those pursuing ambitious or so-called “greedy careers”, amid declining birthrates. For many, their 30s are critical for professional advancement but also a time when fertility declines sharply. Egg freezing offers a solution by allowing women to separate reproductive timing from biological aging, giving them more flexibility and control over their lives and careers.

The underlying premise of egg freezing is that the primary issue that causes a decline in female fertility with age is the egg aging and not aging of the broader female reproductive system itself (e.g. uterus). This is clear in data which indicates that women using younger donor eggs have birth success rates similar to younger women using their own eggs as measured by the percentage of transferred embryos resulting in a live birth. By contrast, women over 35 using their own eggs see a decline in success, with a dramatic decline in one’s 40s.

Despite this, public perception of egg freezing is mixed. Some view it as a false promise, encouraging women to delay childbirth without guaranteeing results. This skepticism stems from outdated technology and poor media coverage. Early freezing techniques used slow-freeze methods that often damaged eggs. But the introduction of vitrification in the mid 2000s marked a turning point. The American Society for Reproductive Medicine (ASRM) has since removed the “experimental” label from egg freezing in 2012.

Yet misleading headlines persist. A 2024 Vox article titled “The Failed Promise of Egg Freezing” cites a 39% success rate, based on a retrospective study conducted over 15 years on 543 women at NYU Langone. However, deeper analysis reveals that the study’s participants were not freezing their eggs at an optimal age, with the median age of egg freezing being 38. When stratified by age and egg number, the story changes: women who were under 38 at the time of freezing and froze 20 or more eggs had a 70% success rate, comparable to IVF using fresh eggs collected at the same age. It is reasonable to speculate that these success rates would be even higher for women freezing eggs at lower ages, but this is not yet confirmed and high quality studies shedding light on this question would be very informative.

Although improving the underlying technology behind IVF is certainly desirable, the bigger barriers to successful egg freezing at the moment are informational and financial. Many women remain unaware of the optimal time to freeze eggs: biologically speaking, between ages 25 and 32. Yet most freeze eggs much later, with the median age across studies being 35.5–38 (meaning half freeze eggs after this point). What’s more, an egg freezing cycle costs between $5,000 to $8,000 in the US, including medication. Simply put: women can least afford to freeze their eggs when it would be optimal for them to do it.

Unfortunately, freezing eggs later not only reduces the chances of success due to a decline in egg quality, but also increases the cost, as older women need more cycles to retrieve enough viable eggs. Another problem is that not all clinics are the same. Survival rates for thawed (defrosted) eggs range from 71% to 94%, depending on the clinic, but data is not consistently reported and some clinics do not show survival success rates at all. It is highly likely many clinics have survival rates way below 71% that they simply do not report.

There are several paths forward. On the scientific front, improving IVF outcomes so fewer eggs are needed could make the entire process more efficient and dramatically reduce costs, as fewer eggs and consequently less retrieval cycles would be needed in the first place.

From a cultural and policy perspective, women may benefit from better education about how important it is to freeze eggs early. This is separate from the moral question about whether we ought to be recommending this for young women in the first place rather than encouraging people to have kids at a younger age. Yet, for women who feel that starting a family would truly hamper their career — as in physically demanding professional sport — policies like the WTA’s offer another route amid a global birth rate crisis.