pale_moonlite prompted me with Minerva and Remus (wildcard genre): Chizpurfle eggs, Knife of Fertility Alteration, and the Corrupt Penguin.
A Knife without Blade (PG; Minerva, other people's sons; 635 words): Minerva assists her godson with a delicate matter.
The potion was called the "Knife of Fertility Alteration"—a joke of the masters that Minerva elected not to think on too deeply—and her need to acquire it had led her to the oddly named pub, the Corrupt Penguin.
"You have what I need?" she asked her surprisingly youthful contact.
He grinned. "Brewed it myself."
"Just because you think it would have upset his father, I think," Minerva replied.
"Certainly not. That was before my time, ma'am."
Minerva removed her spectacles, scrubbed them, and replaced them to peer at the young master. "Ah, so you're Toby, then?"
"I am. Dad sends his regards and regrets. Being dead, he doesn't get out much, you understand."
"I suppose I do."
"Tell the drinker that he needs to be certain. There's no antidote to the Knife. He takes it, she's stuck the way she is—fertile and female forever."
"Of course," Minerva replied, passing a Shrunken carton to Toby. "That's a year's worth of Chizpurfle eggs, as agreed. What will Severus use them for?"
"Actually, I'll be using them to pay off my tab here. Old Migren's a dreadful hag when left unpaid, and I've always had a taste for her beer."
Like father, like son, thought Minerva. "Tell Severus he might write more often."
"Yes, well. Good day to you, young man."
It took longer than Minerva would have liked to travel back to Hogsmeade, but her godson was waiting for her at the Three Broomsticks.
After they'd settled themselves by the fire, she asked, "Remus, er, Rema, are you sure that this is what you want?"
Twirling the phial in his hands, he nodded.
"Even though your parents disapprove?"
"I think 'Teddy' and 'Victoire' will get over it when I present them with grandchildren, Goddie Minnie."
"Show some respect, dear."
"Sorry. It's just been hard."
Minerva hiccoughed. "It won't be for much longer."
"Oh, dear," Minerva replied, without repentance. "It's a serious matter, this."
"It's my matter, and you should know how serious I am about it after making me see the Mind Healer and Squib specialist. I don't just want to change my sex to be a mother. I want to be—I am a witch. You said you understood."
"I do, dear. I just want to be sure that you're sure. Toby Snape says there's no going back."
"Ah, so you did go to him."
"Well, Toby claims to have brewed that himself," Minerva replied, pointing at the phial, "but I expect that's because Severus told him to say as much. He didn't get on with your grandfather, you know."
"Yeah, I've heard the stories."
"Yes, well, you may not speak of Severus, Rema. He likes his privacy."
"I like mine, too, and I'm very grateful to you, Goddie. You're the only one who's ever taken me seriously."
"You were an interesting student. One couldn't help but take you seriously. I only hope that Bertie Bulstrode deserves you."
"You know he does. "Flexible" though he may be, Bertie prefers birds to blokes. Wouldn't you call that sort of patience deserving?"
"I expect," Minerva replied, taking another long drink of her Ogden's Old, "that neither of you will know true patience until your children are born."
Rema laughed. "I can't wait."
"Be a dear and don't make your parents wait to know of your decision. They're just worried about you, you know."
Rema sighed. "It's too bad I didn't end up a Metamorphmagus. That would have made all of this so much easier."
"No," Minerva said. "It wouldn't have done. It would just have frustrated you because no Metamorphmagus can hold a transformation for the duration of a pregnancy."
"Perhaps one never tried before. It's not like there's literature on the subject."
"Yes, but there is the Knife, dear, and now you have it."