as far as my research online, a husband cannot get sc/st certificate if wife belongs to sc/st. a wife on the other hand can get the certificate if she is married to a sc/st, but cannot enjoy any sort of reservations. the child born to a father who is sc/st the child can get it and also apply for reservations, permitted by state and center.
Om prakashji, you are correct. I must have misunderstood it. Somewhere it said a general caste woman marrying a SC/st inherits the husband's caste but cannot enjoy the reservations.
So I thought "inherits" would probably mean she can get a certificate too. My bad. Thanks for correcting