Losing curls with natural techniques

Hi, i am have curly hair , but mine is just a little bit curly. so i wanted to know if there is a natural technique to make the hair straighter with some time, and without using too much products or whatever. My dad has wavy hair, i like wavy hair, he says he had curly hair like mine when he was young and then he got it wavy with aging.
i`m sure that is a natural process, but isn`t there a way to accelerate it?, i just need my hair to be a tiny bit less curly, so it will look like Heath leger.
i am a male and as i said my hair is like first level of curly but it looks more curly than wavy. its strong hair.