If you have an iPhone 4S and a birthday recorder in your calender, all you need to do is ask Siri to remind you about the birthday's of your special one's. Now you don't have to feel bad that you forgot the birthday's of your special one's as Siri has your back.
As explained by TiPb :
Step 1: Keep the Home button pressed until Siri pops up.
Step 2: Ask Siri “When is [name's] birthday”
Step 3: Wait for Siri's answer.
Any name can be entered including your own name , proper names or names of relationships (my cousin's) provided they have been added to the contract.
If Siri would allow to create birthday based reminders, we may never have to worry again. Share your thoughts below on this quick-fix to remember birthday's of your special one's.