You know how Serena Williams is pregnant with her first child?

Well, she was pregnant -- because she went into labor today.

And now the greatest athlete in the world has given birth!

Serena Williams is arguably the most accomplished athlete in the world.

It always warms the cockles of our hearts when we see people congratulate Olympians on being "the best in the world" and they correct their interviewers by pointing out that Serena Williams holds that title.

But even superstar athletes get pregnant, folks.

Serena actually announced her pregnancy by accident over Snapchat.

She's a Millennial, but not of the Kylie Jenner age-group, and Snapchat has a way of making a lot of Generation Y feel hauntingly old (I'm speaking from experience, here), so accidents happen.

Apparently she just "hit the wrong button," and delivered good news to the whole world a little earlier than she and her fiance, Alexis Ohanian, had planned.

Serena Williams' friends have already gushed about what an amazing mom she'll be, and it looks like Serena's chance to prove that starts today.

Us Weekly is reporting that Serena Williams gave birth!

The tennis champion welcomed her first child, a baby girl, into the world today, September 1st.

This is exciting news and we're still waiting for her to announce it herself, but this is a big deal.

We'd already heard that she'd gone into labor, but labor can last minutes or hours and hours and hours.

(The worst case scenario is days, but we think that most hospitals usually intervene before it comes to that these days)

For the moment, we don't know that much more than that Serena has given birth.

She's not usually a shy one -- think of that Serena Williams nude photoshoot -- but we can absolutely understand someone being overwhelmed at the birth of their first child.

The Grand Slam is one of the four biggest tennis tournaments in existence.

Up until now, only three mothers have ever won it.

In the last four decades, only tennis champion of that caliber has also been a mother.

Kim Clijsters won the 2005 U.S. Open, then wnet on a hiatus for most of 2007 through 2009 when she got married and had a baby.

But then she came right back and then won the 2009 and 2010 U.S. Opens.

Serena Williams is the best in the world.

If she wants to, she'll join that very select club of champion moms.

But Serena is already a champion, and she has nothing to prove.

(Though that's never stopped her before)

While she's been an empowering public figure for women everywhere as an athlete, it's amazing for representation purposes that Serena Williams has also become a mom.

Not all women want to be mothers, and not all women have to become mothers.

But while being amazing at your job and being amazing at parenting are both accomplishments, being amazing at both is something that people don't see enough.

Athleticism is too often divorced in people's minds from femininity and nurturing, but Serena's out there smashing stereotypes.

We're very excited.