Even as a personal belief it can be problematic when it causes harm to children you have while your own life circumstances don't really make that a good idea (e.g. being gravely ill and dying soon after the birth, leaving the child a predictable orphan; having genetic diseases that will kill any children you have after significant suffering with no chance of a cure;...). There are always at least two people to consider in any decision not to abort, even if one is only a future potential person (but unlike the decision to abort, where that person does not exist in that future, when they are born they actually can suffer).