When siblings share a womb, sex hormones from a male fetus can cause lasting changes in a female littermate. This effect exists for all kinds of mammals — perhaps humans too.
A sibling can change your life — potentially even before birth. The sex of one fetus can affect its neighbors in the womb. The "intrauterine position effect" was first discovered in cattle farming.
This will be the last chance to catch a total solar eclipse in the continental U.S. for about 20 years, so here's what you need to know to safely enjoy!
The Mexican city of Mazatlán is the first place the total solar eclipse will be visible as it emerges over the Pacific Ocean today, and the weather here is perfect.