When he becomes aggressive on the leash don't make a big deal out of it. Say "leave it" or "no" in a firm voice and then leave the distracted are. Take treats and as soon as his attention focusses on you give him one. If you make a big fuss at that time by yelling or saying "oh its ok, he is a nice man..." then the dog thinks "hmmm Mum/ Dad is upset so this must mean that strange women are bad". My dog at school is the same way and we are working on introducing a watch command so that when he gets excited and growly i can say watch and collect his attention on me. Never punish him for growling as he could learn not to growl, and the next step is biting. A growl is his way of warning.
As for the female dog issuse, make sure that at least 50% of the dogs you let him go up and sniff are female. If he starts making bad introductions (piloerection, growling) then either use a watch command or take the leash and start jogging past or away from the other dog. He needs to learn some introduction skills. This may calm down when hi is neutered as he is past puerty so he might be thinking sexually and not playfully with these females.
A good book you can try is the Culture Clash by Donaldson. She is wordy and does preach from her high horse sometimes, but the information is good.