Late but I think it'll depend where you are and what security features birth certificates where you are have. Where I am, the paper has a unique feel to it and also has one of those little hologram type sticker things on the back. So I imagine laminating it would cause issues in official circumstances where they want to feel the paper. Also not sure if it'd affect the sticker things or not, but the heat from the laminator could cause damage if done wrong

But if the BDM department where you are is lazy and literally just print your info onto an official looking piece of paper, I'd argue the point. I don't see what laminating it would do in that situation, although when it comes to government departments, they don't tend to be very flexible. If you were just showing it to verify your identity or working rights for a job or something I doubt anybody would refuse it in either situation