Let's say you have a girl, 'Jackie.' Jackie never finished college, got pregnant after a one-night stand, talked the guy into marrying her in a courthouse, now lives with her husband and baby in her parents' basement, husband currently being jobless and on probation. Jackie, now waiting tables on the nightshift to pay for groceries, gets pregnant again. Read paragraph 10 of Humanae Vitae
and tell me whether or not this is 'responsible parenthood,' as defined therein. Do me one better and tell me if Jackie had a moral obligation to avoid procreation. Even better, did she commit a sin by failing to avoid procreation?