Women and girls represent half of the world's population. But when it comes to science, women and girls make up far less than half of STEM students and professionals. And some groups, like women of colour and women with disabilities, are even more in the minority.
Today is the United Nations International Day of Women and Girls in Science, and the aim of the day is to shift that equation. But it's not just a matter of numbers.
Encouraging more girls and women to pursue science isn't just about trying to reach a 50/50 split of men and women in the workforce.
Science is all about innovation and solving problems. We need more women, and more diversity in general, to make sure we the have diverse viewpoints and perspectives to find the best solutions.
But this diversity isn't going to just happen on it's own.
We need to make sure we have a system, a culture, that makes everyone feel welcome and included, and remove the barriers that are preventing girls and women from taking up half the space in STEM fields.
We can start by fighting those stereotypes that say that boys are better than girls at maths and computers and engineering - or that girls just aren't interested in these things. Research has shown us time and time again this isn't true.
We can show more female role models - including more women scientists and their discoveries in our school curriculums would be a good start, as would showing more women in science in the media.
We can nominate more women for awards, we can invite women to speak at conferences. We can promote flexible working conditions that allow more people to participate.
We can reassess the ways that we award grants and promotions to remove inbuilt biases that often reward men over women. And we all need to be vocal about the biases or discrimination that we see or experience. As a woman I've found my STEM career to be extremely rewarding.
I have a job that is intellectually stimulating, creative and flexible.
It's a job that's allowed me to connect with so many different people, and taken me around the world. I'm not sure I can really imagine doing anything else.
And on this International Day of Women and Girls in Science, I hope that in the future many more girls and women can say the same.
Dr Mary McMillan is a lecturer at the School of Science and Technology, University of New England