50-50 chance.
With regular seeds, I usually start with either 3 or 6 seedlings. Pretty well guaranteed to get a male out of 6, but 3 can be a pretty safe option to get at least one male.
5 seedlings would 100% ensure at least one if not two males.
Regular seeds are usually much cheaper and starting with 5-6 will give you a choice of males to use for breeding. Having two will usually provide one male that is better than the other, meaning your genetics will benefit from being able to pick the better male plant.
Hope this helps,...... Organoman.