My guess is Alex is a male. Watch out for typical gander behaviors; he might become aggressive in the future. Geese as house pets are wonderful, though. I had a pilgrim goose last year, who tragically passed away at only 6 months old, who was a delight. She wore goose diapers from Nancy and Alan Townsend, although Nancy has sadly passed away. On my goose communities I often hear buzz that http://www.indoorducks.com/ has good diapers for pet house geese/ducks, so you could look there.
I'll probably contact them about sizing some for me shortly...