It is a completely personal choice and i know its a tough decision, but for me it was easy, i'm such an impatient person and like to be able to plan so to not find out wasnt an option.
But even if i'd wanted to wait i'd have found out anyway because my husband really wanted to know. I think its harder for men to bond with the bump and he said that knowing what we were having and being able to call him/her by our chosen name would make it all the more real for him so i'd have found out for him anyway seeing as i get all the amazing experiences of feeling her move etc, that was his little thing he wanted and i wouldnt have stopped him. Luckily though like i said i was too impatient to wait anyway!!!
Good luck with your scan and whatever you decide!!
xxx