Silicon Valley's latest job perk? Egg freezing

Silicon Valley's biggest companies have long offered cushy perks to attract top talent and keep workers happy logging scores of hours on the job. But beyond day-to-day luxuries, Facebook and Apple will now give up to US$20,000 in benefits to help employees pay for infertility treatments, sperm donors and even to freeze their eggs.

The move comes amid stiff competition for skilled engineers, and as many of the biggest firms try to diversify their male-dominated ranks to include and appeal to more women.

"Anything that gives women more control over the timing of fertility is going to be helpful to professional women," said Shelley Correll, a sociology professor at Stanford University. "It potentially addresses the conflicts between the biological clock and the clockwork of women's careers: the time that's most important in work, for getting your career established, often coincides with normal fertility time for women. This can potentially help resolve that by pushing women's fertility into the future."

Facebook this year started offering to reimburse workers for up to US$20,000 worth of reproductive-related costs, over the course of employment. Apple's similar perks will start next year.

Freezing eggs involves removing a woman's eggs and cooling them to subzero temperatures to preserve them for future use and stop the egg from changing and developing. Generally speaking, the viability of a woman's eggs can decline a bit at age 27 before taking a steeper drop around age 34 or 35.

As more women wait longer to have their first child, the number of women choosing to freeze their eggs has grown "exponentially," said Dr Alan Copperman, a fertility specialist at Mount Sinai Hospital. They are also doing it at a younger age, which means healthier and more viable eggs.

Freezing their eggs gives women an option to focus on their career or education first, the "leaning in" that Facebook Chief Operating Officer Sheryl Sandberg champions. It can cost more than US$10,000.