If you’re a company flush with cash and you want to attract a particular type of candidate, what do you do? Easy. You offer the perks that will get and keep the talent you seek in the door.

Tech giants Apple and Facebook want to attract and retain young women and the latest perk they are offering is groundbreaking. The two companies announced that they would pay up to $20,000 for a young woman to freeze her eggs. The goal is to relieve the pressure that the few women in the tech field feel to trade-off career advancement for family planning during those critical career-building years which also happen to be critical child-bearing years.

It’s not outlandish for Silicon Valley to offer top talent unusual perks beyond signing bonuses and stock options like dry cleaning and club memberships. However offering a benefit that would potentially pay for two rounds of egg freezing takes the perk wars to a new level.

Critics worry it sends the wrong message and skirts the benefits that women in the workplace really need like childcare, longer paid maternity leave.

NPR reports:

The addition of egg-freezing to the benefits plan comes as tech companies face mounting pressure to hire more women. And it's a perk that some women may find attractive.

And an expensive one — the benefit covers $20,000 worth of procedures, typically two rounds of egg retrieval. Then again, rich Silicon Valley companies are notorious for high-end benefits that can include gourmet food, dry cleaning and massages.

Facebook told NPR that its offering this benefit because employees were asking for it. In a statement, Apple also said it wanted to make certain its female employees could "do the best work of their lives." Both companies have paid parental leave policies and on-site health care. Facebook also subsidizes day care costs.

But Marcy Darnovsky, executive director at the Center for Genetics and Society, says that expanding benefits to cover egg-freezing could put pressure on women to delay childbearing so that their employer can get more hours out of them. Darnovsky is an advocate for the responsible use of reproductive technologies.

Egg-freezing is no guarantee of having a child, though. Studies indicate that women who have three rounds of egg retrieval at around $10,000 per round have a slightly more than 30 percent chance of giving birth if they are 25 or younger when the eggs are frozen. The closer women get to age 40, the lower the likelihood of success. If women limit themselves to the two rounds of egg retrieval covered by the new benefits, that also will reduce the odds.

These private companies have every right to offer whatever perks they choose to attract female talent. It’s a great sign that the contributions of women –especially budding young workers- are valued so highly. Young women in the tech industry should feel a little more appreciated.

However, they should also be realistic. First, it’s reasonable to expect some sort of commitment. As with tuition reimbursement, there may be a required commitment to the company and each worker must determine whether she is willing to follow-through with that.

Second, and more importantly, they should be careful not to place all their eggs in a frozen basket. This benefit is not the answer to the work-motherhood tradeoff. It only delays the decision –a bit.

As the experts note, those 25 or younger who freeze their eggs have a slightly more than 30 percent chance of giving birth and the closer women get to 40 the lower the likelihood of success. Fertility treatments are expensive, painful and still may not work. This perk helps defray some of the costs but not all of them.

Some women who would ordinarily prefer to have children earlier also might opt to delay parenthood because of this new perk.