There is absolutely no way to tell a male seed from a female seed.!!
With plants it is very difficult and there is no 100% certain way to tell before flowering commences.
Generally though, males will grow faster and taller with fewer/smaller branches and females will grow slower and have longer branch growth earlier, but this is not a 100% reliable method as I have had very bushy/branched males and very tall females without much branching.
Another method is to look at your seedlings at night, it seems females will have their leaves folded downwards towards the main stem and males will keep their leaves in a more horizontal position, but again, this method is not 100% reliable, but it is a good clue.
In a lab they will identify the plants chromosomes which will indicate either male or female. Obviously this technique is expensive.
Buying feminized seeds solves a lot of guess work.
Pev Grow in Spain would be able to send some seeds to you.
I have been using them for years with 100% postage arrival success.
Hope this helps, Organoman.