So now if one is considering buying bitcoins and saving for his/her children in the future is there any way to do that with bitcoins apart from having to write down your details somewhere. I'm asking because with that kind of stuff if no one knows your seeds or password no one can get the coins. 
You can write the login details for the exchange on a paper and put it in a locker. This approach is not advisable in my opinion if you have children below 5 or so. By the time they are 20-25, bitcoins might not even exist.