Marissa Mayer’s appointment last week as the new CEO of Yahoo! is a sign of progress for women in high-tech. A trail-blazer as the first female engineer hired by Google, Mayer now becomes one of Silicon Valley’s corporate leaders. At a time when just 10% to 20% of upper management and corporate board positions in Western nations are filled by women, this is certainly good news. But the terms of her appointment are stirring up controversy. Mayer was hired several months into her pregnancy. And she plans to work during her pregnancy — a commitment no doubt intended to ally concerns of (male) shareholders and business analysts who have roundly criticized Yahoo’s recent decisions (its previous CEO was fired when it was discovered he lied about his credentials). So the issue Mayer’s approach to work-life balance raises is the trade-offs women have to make as they reach the pinnacle of corporate power. Delay your family (she is 37), take minimum time off for child care, and have enough money to hire good help (Mayer’s wealth comes from being one of the early Google employees). But reality is very different for the average working woman with career aspirations. In Canada, there is a rise in human rights complaints related to discrimination against pregnant women. Women still are being illegally fired in this country for being pregnant. And there is clear evidence that work-life balance has become more difficult. This is based on new survey data from Ekos Research Associates, which compares work-life balance in samples of the Canadian working population between 2004 and 2012. By all means, let’s celebrate Mayer’s success but let’s also recognize that it comes with sacrifices that many other women don’t want to make, or can’t make.