Have not heard about the sterilisation bit, what has been happening of late until recently is that only males are available for sale. You cannot tell if a male is sterile, best course of action is to see what happens.
How large is your tank? These gourami can be very aggressive to co specifics, especially the female, so offer plenty of plants for them to hide in or they will get beaten up.
The females usually do not show much colouration, blue bars show faintly over the dull grey if anything. They can hold all of the colour morph genes - red, blue and classic striped, so it is a bit pot luck what you get when they breed.
If you see them breeding the best course of action if you wish to raise the fry is to remove the bubble nest after they have finished by scooping the whole thing up in a container that you can float in the tank too keep the temp the same as the main tank. After they have hatched and are a few days old you can put them in a tank that you have setup with a sponge filter and a low water level to grow them out. Beware - my first spawn saw me feeding and raising about 80 fry on Liquifry then BBs for weeks!