Susan and Anne Wojcicki

FORTUNE — For the first time since the FDA came down hard on 23andMe for marketing its DNA tests without proper approvals, founder and CEO Anne Wojcicki spoke about “the big challenge,” as she called the firestorm, in an exclusive interview with Fortune.

I talked with Anne and her older sister Susan Wojcicki, Google’s SVP of Ads and Commerce, on stage Tuesday evening at a
Most Powerful Women event in San Francisco.

“We failed to communicate proactively,” Anne Wojcicki told the Fortune audience of 100 women leaders. Now scrambling to comply with the FDA’s demands, Wojcicki has stopped advertising 23andMe’s $99 DNA test kits. Meanwhile, she’s facing a class-action lawsuit that claims that her company’s ads are misleading and the results of its genetic tests aren’t supported by scientific evidence.

23andMe has plenty of financial backing to weather this storm: $126 million in funding from Google, Johnson & Johnson and Russian billionaire Yuri Milner, among others. Nonetheless, this is a seriously tough period for one of Silicon Valley’s rising star entrepreneurs. Earlier this year, Wojcicki separated from her husband, Google co-founder Sergey Brin. The couple has two children.

Elder sister Susan and their mother, Esther, who was in the audience Tuesday evening, are offering helpful advice. To solve any problems, Esther told her daughters, you need to break them down: “Big challenges are an accumulation of small challenges,” Anne said she learned from her mother.

Susan Wojcicki sympathetically noted that the genetics industry is a lot like the Internet was 15 years ago—a Wild West where the rules are newly forming and pioneers are constantly scrutinized. “In some ways, both companies [Google and 23andMe] are doing things that have never been done before,” Susan said.

For more on 23andMe’s FDA challenge and my exclusive interview with the Wojcicki sisters, read my colleague Michal Lev-ram’s post here.