Have you read this Dirk?
http://www.loaches.com/articles/sexing- ... yzon-cheni
There are differences in body shape and colour as well, but they won't be easy to spot in small fish.
These are the best photos I have of my two biggest fry- they're over an inch now, but still much less bulky than the adults. The second is a little bigger than the first.
I think the first is probably male, and the second maybe female, based on body shape and colour, but I'm really not sure. They both have visible tubercules at this size, but they're not easy to see. In less than ideal conditions such as a shop tank they might not show up.
Possibly male:
Female? Looks a lot like it's mum anyway:
Cheers mick- I'd love to see some pics of your fish. I've never really made a definite id of these guys, just always assumed they're cheni.