United States' Serena Williams holds her trophy after defeating her sister, Venus, during the women's singles final at the Australian Open tennis championships in Melbourne, Australia, Jan. 28, 2017. Williams famously won the tournament when she was eight weeks pregnant. An expert said mothers often are better athletes because they learn how to manage their time better, they understand their bodies better and they may be peaking even later in life. (AP Photo/Dita Alangkara, File)
