Serena addressed the comment in an Instagram post.
Ilie Nastase, a 70-year-old former world No. 1 tennis player from Romania, is reportedly under investigation for allegedly making a racist comment about Serena Williams' unborn child.
According to ESPN, the former tennis star was overheard making a comment about the color of Williams' child at a press conference.
"Let's see what color it has. Chocolate with milk?" he reportedly said, per ESPN.
Williams is expecting her first child with fiance' Alexis Ohanian, the co-founder of Reddit. Ohanian is white.
She addressed the alleged remarks by Nastase on Instagram earlier this evening.
"This world has come so far but yet we have so much further to go," she wrote.
The International Tennis Federation said the following about their investigation:
"The ITF does not tolerate discriminatory and offensive language and behaviour of any kind. We are aware of alleged comments made by Romanian captain Ilie Nastase and have begun an immediate investigation so that we have the full facts of the situation before taking further and appropriate action."
Earlier today, Williams posted a loving note to her unborn child.