In Silicon Valley, the definition of a unicorn is a start-up company valued at over $1 billion. Unsurprisingly, three elusive unicorns have women founders/CEOs. Stitch Fix’s Katrina Lake changed the way women shop, Houzz founder/CEO Adi Tatarko revolutionized the home improvement industry and Anne Wojcicki brought genetic testing home, literally, when she created 23&Me. Read more.