These days, machinery does most of the heavy-duty work. Plus, we have social systems that allow men and women to take equal maternity and paternity leave, nurseries and childminders to look after kids, and men and women are equally capable of firing a bullet (despite the statistics that show that men should be trusted far less with firearms).
Girls can like tractors, Lego, spaceships and racing cars. Boys can like dolls, dressing-up, and playing with a toy kitchen. Girls can grow up to enjoy maths and science. Boys can grow up to enjoy reading and painting.