The start of pregnancy — as well as exactly when that happens — is a hot topic in some state legislatures and U.S. courts. Understanding the... Pregnancy is often talked about as though it's a light ...

Corrections & Clarifications: An earlier version of this story misstated how to calculate pregnancy duration. It has since been updated. If you think there's a chance you might be pregnant, you want ...

Pregnancy is often talked about as though it’s a light switch. You’re a regular person walking around and then a switch flips — presto, you’re pregnant. The reality is more nuanced. "Sex ed really ...