Oh I know. I mean you know I live in the South and because we don't have good sex ed and abstinence only education our teen pregnancy and repeat teen pregnancy rates are astronomical. Hell with Roe V Wade being overturned we are going to see even more butt loads of teens having babies.
In fact like I stated before the situation was so bad at my brother's high school they needed a daycare center there because of how many girls kept popping out kids.
Though even in the teen mom and dad situations usually they have parent supervising them. Haruka and Michiru have no such thing. They basically act like adults while being in high school. I could see Chibiusa do that IE use the Luna P ball to brainwash some government officials to let them keep Hotaru though also Haruka and Michiru probably have enough money to bribe officials without having to call for Chibiusa's services.
Bribery is probably not their interest, it´s too obvious. Most cases of bribery are where you could plausibly destroy all evidence, that people want that evidence destroyed or hidden, or if the official could make some kind of judgement call like a cop deciding whether or not to warn a speeding driver. In Japan, as it stands now, it´s simply that if it isn´t one male, one female, each at least old enough to marry which I think is 16 or possibly 18, then a civil servant doesn´t have discretion, and being masculine or feminine would be a fundamental part of an identity you either can´t hide or really wouldn´t want to hide. Hypnosis of civil servants to act the way the Tsukinos did when they never questioned why some unusual child they are suddenly raising doesn´t appear to have natural documentation might make more sense to me.
At least Michiru and Haruka seem to be very rich, demonstrated by the fact they own a helicopter, and several sports cars, Haruka´s apartment costed a million yen per month, and they have that nice dacha somewhere as seen in the first couple episodes of Stars. Paying for childcare seems to be well within their capacity. And Hotaru grows up quickly enough that they can leave her alone within a couple of months, if she´s ever bored she can just go phone up Usagi to ask if she can play with Chibiusa.
Actually, come to think about it, Usagi is a weird example of the verb tenses around being a mother. If it is a known fact that she will be at a given point, and then Chibiusa comes back from the future in her Delorean, er, I mean, time key, is she already one? She doesn´t have the problem of financial support, pregnancy, giving birth, breastfeeding, and caring for an infant to deal with, but she does have to adjust her life in the sense of being a role model, or at least trying to be one, that´s a lot of pressure for a sixteen year old girl (and same with Mamoru of course). At least at that point it´s not too different from being a much older sister.