Hi - i agree with aussienic, you wont treat them the same, and that is purely because they are different people and have different needs.
My sister and I were treated fairly but not the same, how could we be, although there is only 16mths between us, there were so many differences and to treat us in the same way would have been unfair. I always thought that my sister (younger) was treated better and allowed to do things earlier (i still half joking whinge to Mum that she should have made my sister wait another 2 years before getting her ears pierced - i had to wait until i was 14, but she got them done on the same day!).. that was just a petty little thing really - but if my sister was treated the same as me she would not be where she is now, she found growing up really hard and was given allowances that i was not - i needed to be pushed and have limits set - she needed more flexible gounds otherwise she would have left or rebelled...
Anyway what i am trying to say is, dont feel bad about treating them differently as they need to be to a point (favouritism is something different) as they are different people and will have different needs to develop into who they will eventually ecome.

DSS has had some awful times at school and it breaks our heart when he comes home sad because noone will play with him, but i rememebr being bullied at times too - looking back it must have been really hard for Mum, but she just provided us with the love and support that we needed at home and reasurred us that we were good people etc.
I am rambling now - sorry

I hope this helps Goodluck