You have every right to know. Maybe ask an aunt or uncle or a long term friend of your mothers
Start with your birth record?<br />
Usually parents have a reason for not letting their kids know such things... Leave it be till he couldn't be a risk to you and your mum anymore... So till your off age...
i had the same problem but one day mum came into my room and told me everything she's waiting for the right moment
You could maybe ask her to participate in some family counseling.