If either the male is neutered (plus a month) or the female is spayed, they will not be able to impregnate the female, however, it is never recommended to put two bunnies together where both haven’t been fixed. This is due to the fact that the hormones intact bunnies have cause them to be very unpredictable and frustrated, and it is probable that this will result in fighting, or even injury to the bunnies or the bonding they could have the future. For this reason, it is always best to have them both fixed (+ one month) before attempting bonding.