Pokes Gender

Nidoran.

The game even helpfully labels their gender in their names! :P

What's true here, is true in Pokemon Go: http://bulbapedia.bulbagarden.net/wiki/List_of_Pok%C3%A9mon_with_gender_differences

Heracross. Different horns. Females are more rounded and short. Males' are sharper, more angled

Raichu you can also determine by the tail. Male is pointed, while a female's tail is flat.
Venusaur - female has a bulb, male does not.
Rattata and Raticate - male has longer whiskers.
Kadabra and Alakazam - same as above.
Doduo and Dodrio - male has black neck, female has light brown.
Magikarp/Gyarados - male has yellow/blue whiskers. female has white.
Scyther and Scizor - female's lower section of body is longer
Sneasel - male's red feather thing on the head is longer.

Ursaring: female has longer shoulderpatches.
Steelix: Male as an extra hump near his eye
Politoed: male has a bigger spot on his cheek

Never noticed it before, but my male shiny Gyarados has red whiskers....

Female Hypno has fluffier collar.

Murkrow. They have different size "hats"

Gligar

Make Rhydon has a longer horn then female Rhydons.