When Wilson Sonsini Goodrich & Rosati announced that the firm had helped Polycom Inc. buy Hewlett-Packard Co.’s Visual Collaboration business, it looked like a typical M&A deal. But on closer inspection, it wasn’t. With one exception, all the lead attorneys on Wilson’s team were women.

“I didn’t notice it until someone pointed it out to me,” lead corporate partner Melissa Hollatz said. “It wasn’t anything deliberate, but it is highly unusual, and it is nice.”