Well, technically, it is a sin for a Sikh to marry a non Sikh. When the Sikh rehat maryada was created (the Sikh way of life), its wasn't just a bunch of random people creating rules out of nowhere. These highly religious and intelligent individuals decided this for a various amount of reasons. When someone does what they think is right for you, do you question them? If a parents tells his child, do not stick your finger in the electrical outlet, he must be telling you for a reason. The child does not know the reason and might think that his dad is scolding him frivolously (sp? sorry), but we know that he or she is doing what is right for his child. Even though we might not be told a reason, the rehat marayada tells us that we should not marry a non-Sikh and that should be the end of the discussion.

~Preet