You've got some good advice. There's no way to know if you've only got the beans to go by. There's no way to look at them to see if the spots tell you anything, and the whole leaf display thing is pretty much crap too. Males and females are identical in every way, because the plant doesn't sexually differentiate until the last 2 weeks of veg before alterating nodes form. The chances are that 50% of the beans you plant will come up male, so all you can do is play the numbers.
At this point, you can try to force flowers by inducing a 12/12 cycle on one branch (by using either a darkening bag over the branch or by poking the branch through a hole into another chamber). These work with varying degrees of success - especially if you're forgetful like me
Good luck
