One rarely uses the term genius for living people. I made an exception for Maryam Mirzakhani. Sadly she died of cancer at forty today. Here's a piece on her in Quanta after she won the Field Medal - the highest prize in math.
a short high level summary of her work by Jordan Ellenberg for non mathematicians
Mirzakhani, whose work expertly blends dynamics with geometry. Among other things, she studies billiards. But now, in a move very characteristic of modern mathematics, it gets kind of meta: She considers not just one billiard table, but the universe of all possible billiard tables. And the kind of dynamics she studies doesn’t directly concern the motion of the billiards on the table, but instead a transformation of the billiard table itself, which is changing its shape in a rule-governed way; if you like, the table itself moves like a strange planet around the universe of all possible tables.
sighs .. some commentary is important:
She is the diametric opposite of what Trump and the Republican Party stand for. Brilliant, math and science literate (they reject and abuse both), female, and from an Islamic country. She was a professor at Princeton and Stanford. Now her sort would not be welcome in American and we will be poorer for it.