Facebook and Apple have become two of the first major companies to offer an interesting perk for female employees: Egg freezing. Since January this year, women at Facebook have had the option of having their eggs harvested and frozen, for future in-vitro fertilization (IVF) -- and from January 2015, women at Apple will be granted the same benefit. Is this just the next phase in the Silicon Valley "perks arms race," or, from a more cynical perspective, is it just a way to keep female employees focused on the prize?