For the best experience, please enable JavaScript in your browser settings. Following the Kakamega twin puzzle that has drawn the attention of the entire country, we ...

Their children are genetic siblings, known as quaternary twins. After identical twin sisters from Delaware married identical twin brothers from Tennessee, the children they are raising together share ...

When you’ve just had identical twins, it’s normal to spend a lot of time looking down at their squishy little bodies and analyzing every subtle way they differ from one another. Unlike fraternal twins ...

Although there are some rare exceptions, identical twins are almost always the same sex. Because identical twins occur when a single fertilized egg splits and forms two embryos, each embryo has the ...

You've probably heard of identical and fraternal twins, but a report published Thursday says there's a third kind -- sesquizygous twins or "semi-identical." Identical -- or monozygotic -- twins pop up ...

The Science of Siblings is a new series exploring the ways our siblings can influence us, from our money and our mental health all the way down to our very molecules. We'll be sharing these stories ...