The only way to sex a gosling that isnt a shetland, cotton patch, or pilgrim (all are sexlinked) is to vent sex them, you look for the same things as you do with ducks, so if you know how to do that then you can do it with goslings. It is hard for me to describe it, it is easyer to show. Maybe go on youtube and see if there is a video about sexing ducklings/goslings, they have videos about everything, even of a chick falling asleep.