Periods: What Should You Expect?

Emily Santora

Sometimes things don’t work as you expect them to, including periods. Learn more about what causes some girls to have irregular or painful periods.

Intersex: More than Male and Female

Risa Schnebly Riley McInnis

You might think that people can be born only as either males or females. In fact, lots of people are born with a blend of male and female traits. We call this being “intersex,” and it happens more often than you may think.

Xs and Ys: How Our Sex Is Decided

Risa Aria Schnebly

Our biological sex determines a lot about the way our bodies look and function. But what determines our biological sex?

Focusing on Female Infertility

Emily Santora

What happens when a person wants to have a baby, but after years of trying, it just doesn’t happen? A lot of people want to become pregnant, but let’s learn about what may prevent pregnancy.

Shedding Light on Endometriosis

Emily Santora

A lot of illnesses, like colds, have very visible symptoms, but other conditions are not so obvious. Learn about how people spot and treat a condition called endometriosis.

Helpful Sex Hormones

Risa Aria Schnebly

Our biological sex is mainly controlled by our sex chromosomes. But sex hormones also influence what body parts and characteristics we have.

Menstruation Matters

Emily Santora

Periods are a natural, normal part of life, and many people around the world experience them. So let’s talk about why and how they happen.

Getting to Know the Germ Layers

Claudia Nunez-Eddy Risa Aria Schnebly

Almost all life forms start out as small cells, but how do they grow into entire animals? Read about the first step here: when cells in an embryo form germ layers that give rise to every organ and tissue in the body.