These differences are the outcome of the punya-paapa (good-bad) deeds done in the previous births. Suppose a person is always kicking the cross of Jesus. Tell me, what is the use of giving him legs?

A person who constantly uses foul language will be born dumb in another birth. (Our dharma shastra granthas contain a section called ‘karma vipaka yogam’. This explains how the present birth experience (both good and bad) are the outcome of the good and the bad deeds of previous births.)

(Q&A Glimpses of Bhaktimala )