Former world number one Ilie Nastase is being investigated by the International Tennis Federation (IDF) after making a racist comment about Serena Williams' unborn baby.
The Romania Fed Cup captain, 70, made the remark in Romanian at a news conference ahead of his country's play-off match against Great Britain.
Tennis star Williams announced she was pregnant on Snapchat on Wednesday, posting a picture of herself in a yellow swimsuit with a prominent bump and the caption "20 weeks".
During the news conference, while another player was answering a question, Nastase could be clearly heard saying to the other players: "Let's see what colour it has. Chocolate with milk?"
The baby - which is due in the autumn - will be Williams' first child with fiance Alexis Ohanian, 33, the co-founder of the website Reddit.
The IDF has said it does not tolerate "discriminatory and offensive language" and will take "further and appropriate action" once they have "the full facts".
It is not the first time Nastase, nicknamed 'Nasty' during his playing career, has made controversial comments about Williams.
In an interview with Romanian media earlier this month, he made unsubstantiated allegations of doping by Williams based purely on her physique.
Earlier this week, when posing for photos with Great Britain captain Anne Keothavong, he also made off-colour comments about coming back to her room.
After asking for her room number, he told Keothavong, who is married and 18 weeks pregnant with her second child: "We keep being attracted."
Williams' baby news means the 35-year-old will miss this year's Wimbledon, having previously won the tournament seven times.