Veronica let your parents know...same gotra means same bloodline. The bloodline goes back several thousand years ago and may be the bloodline has been watered down so much its very unlikely for you to bear dis-formed babies with him. Tell them Ranas and Shahs marry their cousin and only few of them are dis formed and have mental issues.

If you are not leaving him at any cost then your problem is already solved. You can marry him at the COST of your Gotra. : )