Mackenzie's other half-sister, Chynna Phillips, is speaking out to support her. "[Incest] is not something people feel comfortable talking about, and she had the courage to come out and talk about it, and I'm proud of my sister," Chynna says. "But am I exceedingly joyful that my family secret that I told maybe my therapist, my husband and my very best friend in the world [is now public]? No."
Chynna says she learned about Mackenzie's sexual relationship with John about 12 years ago. Mackenzie told her over the phone, and Chynna says she believes her sister. "Who's going to go out of their way to say, 'I had sex with Dad'?" she says.