Because it’s 2019, dude.
If you teach your son to surf, you should teach your daughter. In doing so, you teach her she is just as valuable and just as worth investing time in as a boy might be. This gives her a value as a woman that will carry through her entire life. If her father thinks she’s valuable enough to invest time in, then she will accept nothing less in the workplace and in all other relationships.
Perfect. I been teaching my little princesses to hunt and fish and be 'tomboys' but at the same time, I'll sit down and let them paint my nails or make bracelets and do 'girlie' things with them. Jusst the time put in is where the real value is found. They have interest in my interests and as such, I try hard to find interest in theirs. Give and take, as it were.