Indeed, except for the rare corporation where a woman follows a woman CEO—Xerox is the textbook case—guys typically place women in top positions.

And it’s up to smart women to take advantage of this. Like Annalisa Jenkins, who today announced her move from Bristol-Myers Squibb to Merck Serono, a Swiss-based pharma and biotech giant not well-known to Americans but once related to Merck in the U.S. “I’m leaving BMS for a rather big stretch opportunity,” Jenkins told me in an email. A little-known exec with an unusual pedigree, Jenkins began her career in the British Royal Navy as the first female physician ever to serve at the front line. That was during the Gulf War. Upon becoming a cardiologist, Jenkins joined Bristol Myers in 1997. She rose to SVP, Global Medical, which has her overseeing the company’s medical division worldwide.

And now Jenkins, 46, is moving to Merck Serono to be global head of drug development and medical, she told me, because this is a chance to lead research in cancer, multiple sclerosis, brain disease…and because a few good men steered her there. Jenkins says her supporters include some consultants at Boston Consulting Group and McKinsey & Co., who got to know her while doing work for Bristol-Myers, and Merck Serono’s new top management (male), which has diversity goals high on the agenda. A new female COO and Jenkins both are being added to the management board.

As Jenkins sees it, why not jump on opportunity?

“This is a good example of sponsorship,” she says, explaining that she learned about the importance of “sponsorship” from Sylvia Ann Hewlett, a diversity expert and a friend of hers. Hewlett happened to share a stage with me on a women leaders program in France last month. And as she explained there, sponsors, which are sort of souped-up mentors, constantly look for ways to advance you—all the more key when you’re too busy just doing your job to plot your own career.