Part of the point though was for some reason the number of them. If we didn't need the large amount in the digestive system but still needed it for lungs and e

Part of the point though was for some reason the number of them. If we didn't need the large amount in the digestive system but still needed it for lungs and eyes, looking at the number and saying it's only 1% wouldn't have any real implication for whether the offspring would be viable if it would have messed up lungs and not be. Aside from that though, it may be important, but there are also lots of cross-species animals (ligers, mules, etc.) that don't get the full bacterial dose from the father of which half of their genetics come from and that doesn't seem to be a main cause of any of their problems that I've heard of.