This is all because of lack of knowlege regarding sexual reproduction. The early organisms in the earth used to produce off-springs asexually. i.e. a single organism would reproduce offsprings just by mltiplication of his cells. So, the offspring would have only those characters developed by his father. Due to this fact the evolution was a very slow process. Organisms started reproducing sexually because one partner from one place would mate with another partner from a different place, and with different capabilities, and the offspring would have capablities of both the organisms.. This resulted to a fast rate of evolution...( it would be even faster had it been that 3/4 organisms come together and mate and share their Genes(characters)..you see people are starting to enjoy having group sex..this may be the initial phase of the new kind of reproduction where more than 2 organisms come together and share their genes..you may consider it a crazy idea but yes...every monkey considered the first monkey as crazy who stood on his two feet for the first time.. nature changes..it has to change ) Now you know the importance of sharing Genes and the role of sex in making it happen... It is obvious that sharing of genes by two organisms with similar genes is not very fruitful..that is why our religion prohibits from marrying withing the same "Gotra". It is encouraging to mate with a person with different genes..so that the offspring will have characteristics of both of them. Otherway round, marriage between two people with very different Genes will be most fruitful and should be encouraged most. So I am very strong supporter of inter-cast marriage. I would recommend marriage with an foreigner if it is possible. You try to ovserve nature...Take any tree as an example.. The trees have both male and female part in their flowers.. But they wont be able to reproduce until some kind fo wind or flies or bees etc come and mix the male part with the female part..why did nature designe them like so...wont it be easier if they would automatically combine and reproduce... Here lies one of the greatet mysteries of the nature..you have to understand it by your heart..Nature did so because only then there would be a probablity of sharing of Genes by different Trees..male part of one tree would be carried to female part of another tree by flies,bees or winds..there by making them able to share Genes... Considering these all facts...why are you afraid to share your Genes with a Chetri..go ahead... your offspring will have characters of both chetri and bahun...will have high probablity of existing in the race of world. My best wishes with you.. "Aama Prakriti le Sabaiko Kalyan Garun"