Serena Williams thanks mother for being a role model after athlete becomes new mom

Metropolitan Museum of Art Costume Institute Gala - Rei Kawakubo/Comme des Garcons: Art of the In-Between - Arrivals - New York City, U.S. - 01/05/17 - Serena Williams. REUTERS/Lucas Jackson - RTS14PXO

Serena Williams wrote a letter to her mom thanking her for being the role model she says she needed.

In an open letter to her mother posted to Reddit , new mom Williams calls mom Oracene Price "one of the strongest women I know."

Williams mentions some of the criticisms she's endured about her muscular body, before telling Price she's proud that "we were able to show them what some women look like." She adds "we are curvy, strong, muscular, tall, small, just to name a few, and all the same: we are women and proud!"

Williams says she hopes to "have the same fortitude" in raising her own daughter, Alexis Olympia, who was born on Sept. 1. She signed the letter: "your youngest of five."

Williams is engaged to Reddit co-founder Alexis Ohanian. They welcomed their first child together, a girl, Alexis Olympia Ohanian, Jr. in September.

The Associated Press contributed to this report.