Sikhism
The practice is totally forbidden, if a Sikh does marry out either male or female they will become apostate of the faith which is generally resulted in being disowned or exiled. It is thought that in reality marital conversions do not have to be male dominated as it can work both ways. Inter-religious marriages however through Sikh history have taken place in rare circumstances have followed through with heavy consequences which were difficult to bear for some people and the marriages tend to break.
Read more about this topic: Marital Conversion