There’s nothing celebrities love more than throwing extravagant parties for their children, but Serena Williams is opting out when it comes to her daughter Olympia Ohanian’s upcoming first birthday.

The tennis champion and her husband Alexis are Jehovah’s Witnesses, and Serena recently explained that members of the religion don’t do the whole presents and cake thing. “Olympia doesn’t celebrate birthdays,” Serena said at a press conference. “We’re Jehovah’s Witnesses so we don’t do that.”

According to the religion’s official website JW.org, Jehovah’s Witnesses don’t celebrate birthdays “because we believe that such celebrations displease God.” The site also explains that “Although the Bible does not explicitly forbid celebrating birthdays, it does help us to reason on key features of these events and understand God’s view of them.” One of the reasons mentioned is the belief that birthdays have pagan roots.

Serena also talked about how baby Olympia is doing, saying she’s “not very good in the car” and that she and Alexis are working on it. “That’s one of the toughest things we work on,” Serena explained. “She’s not good if we’re going on more than a five-minute ride.” (Cosmopolitan)