If you are seeing a Suggestion that the mother was too young or something like that, you can select False Suggestion on the Suggestion Status, enter a comment that is appropriate so that if the False Suggestion is seen when another Suggestion is shown for that person, the updater will know why False Suggestion was selected.
If it is just the Red Box when you try to save, you have to select Save Anyway. It would be a good idea to have something in a Research Notes section with a comment about the discrepancy so if someone reviews the profile before saving it, they will know about it.
A birth that is early, so it is less than 7 months between children will cause the Red Error, but frequently, it is valid because a birth year is incorrect. it does come up if the mother's death year is the same as the child, ie died during childbirth or shortly thereafter. Nothing you can do about that, but in most instances, it is valid and the computer is trying to make us check everything.