Jobs was already CEO again long before he had terminal cancer. Yahoo (presumably) knew Mayer was pregnant when they hired her, and made the decision anyway. Big difference.
That's a pretty big assumption.
Would she have been legally required to inform them before being hired?
Unfortunately, the end result is that someone gets screwed either way: either the child misses out on his mother's attention during the most crucial moments of his growth, or Yahoo gets a CEO who isn't focused on restoring Yahoo.
Your statement implies that a woman can not do both. I know my wife would strongly disagree. I suspect many others would too.
http://postcards.blogs.fortune.cnn.com/2012/07/16/mayer-yaho...
> Mayer first disclosed to the Yahoo board that she is pregnant in late June, in a meeting with Michael Wolf, a member of the board's four-person CEO search committee. A meeting with the search committee followed, and then Mayer met with the full board last Wednesday. None of the Yahoo directors, she says, revealed any concern about hiring a pregnant chief executive. "They showed their evolved thinking," says Mayer, who got the phone call last Thursday that she was the board's choice to be CEO.