Madonna has always been an example of a strong, subversive woman in the music industry. But her speech at this weekend's Billboard Women in Music Awards — where she was honored as Woman of the Year — highlighted her struggle as a female in an industry that historically favors men."Thank you for acknowledging my ability to continue my career for 34 years in the face of blatant misogyny, sexism, constant bullying, and relentless abuse," Madonna said, effectively silencing the entire room of attendees. But she continued, bravely recounting the story of her rape on the rooftop of a New York City apartment building, as well as the backlash she encountered from both men and women as a female performer who owned her sexuality.But one of the more poignant points of Madonna's lacerating speech was the music industry's unwillingness to support women of a certain age. She sent out a warning to women, detailing the "game" they must play in order to survive as a musician. The caution finished with a whammy: "And finally, do not age. Because to age is a sin. You will be criticized. You will be vilified. And you will definitely not be played on the radio."Madonna's warning is more true than we've likely realized. Female musicians have a much harder time maintaining a career over the age of 40 than their male counterparts. Think about it: David Bowie recorded well-received music until his death earlier this year at the age of 69. The Rolling Stones just released their 25th album this month, even though most of their members are well into their 70s. And older men in the industry are pulling more coin touring than their female counterparts. According to Billboard , Bruce Springsteen & The E Street Band headlined the highest-grossing tour of 2016 as of July. Madonna was second, pulling in over $123 million. But she was also the only female act over 40 on the entire list. As for the men? Aside from 'ol Brucie, you have The Rolling Stones, David Gilmour of Pink Floyd, and Iron Maiden — so four out of 10 spots are taken by dudes over 50. Angry yet?What's more is that these aged male rock stars maintain the status of "sex symbol" they earned in their youth. Mick Jagger just welcomed his eighth child at the ripe old age of 73 and no one batted an eyelash. For older female musicians, their sexuality is a joke to be made on Twitter. Madonna, who was once the pinnacle of sexiness, walked the red carpet at this year's Met Gala in a sheer dress that exposed her (amazingly taught) butt. When she was younger, this look was her signature, and one that launched a thousand look-alikes. But this year, she was smeared, and the image was slapped across a handful of "worst dressed" lists.