How do you tell the difference in gender of a Mollie fish?

Question

How do you tell the difference in gender of a Mollie fish?

Answer 1

You can tell by looking at the anal fin. Only males have the tubelike structure called the gonopodium.

On left is a male, while on right is a female.

Answer 2

This is a male in the pic www.aquaticcommunity.com/livebearer/molly.php
and this is a pic of a female www.aquariumfish.net/images_01/molly_gold_dust_female_100704