Gender means nothing when it comes to bonding. It all comes down to personality. Unfortunately, bunnies do not develop their personalities until they reach adulthood. I agree with the others. Baby bunnies love everybody. They can seem like they are bonded, but a true (i.e. lifelong) bond can only be established between adults that have compatible personalities. Sometimes people keep babies together and everything works out in the end. Often times, that isn’t what happens at all. Like the others have said, hormones can cause babies who “love” each other to suddenly fight. The change can literally happen overnight, with little to no warning. If they don’t fight, there is the risk of baby bunnies having baby bunnies… which isn’t good. So I would definitely advise against keeping a young male and female together because you don’t know when they will be capable of reproducing.
If you are set on getting two babies, it is best to keep them separate until they are old enough to be spayed and neutered. Then you can begin the bonding process. Ideally… it would be even better to get the female, let her grow up, have her spayed, etc. By that time, her personality will be known. And you could look for a friend for her (male or female) that will be a good match.