Poppy looked up from her crepe-paper bows for the first time. “I have to be alone?”

“Well, because your friends don’t know … you know … quite who you are.”

“Who I am?”

“I mean they know you, of course, but they don’t know. You know?”

Poppy looked confused. “Are you being silly, Mama?” She concluded her mother was just teasing her and broke into a huge almost-seven-year-old smile. “Don’t worry. This is going to be the best sleepover ever.”

But Rosie worried anyway. “What are we going to do?” She was whipping green cream-cheese frosting, as instructed.

“See how it plays out?” Penn guessed.

She pointed a whisk at him. “You’re the one who wants to keep this thing a secret.”

“I don’t want to keep this thing a secret. We have all, prudently, agreed to this approach for this moment. For good reasons.”

“But it’s like she didn’t even know what I was talking about. It’s like she’s forgotten she’s really a boy.”

“She’s not really a boy.”

“Yes, right, I know, I know. But you know what I mean. It’s like she’s forgotten she has a penis.”

“When you own a penis”—Penn glanced down at his authoritatively—“you never forget.”

“She’s forgotten that a penis isn’t what she’s supposed to have,” Rosie persisted. Maybe she couldn’t quite articulate it, but she knew the point was valid. “She’s forgotten her friends have—and are expecting—something else.”

Rosie had taken to trying to walk around naked more, but it was hard. For one thing, there was the mob of teenage boys in her house. For another, there were the neighbors. The problem was the kids saw each other naked all the time, changing in and out of swimsuits and sports gear and school clothes and pajamas, and Poppy therefore had the impression that she was totally normal. Everyone had toes. Everyone had elbows. Everyone had a penis. Maybe it lacked subtlety, but Rosie thought “show don’t tell” was the best way to disabuse Poppy of this last point. She sat in the bath until her fingers wrinkled into origami so that she could be getting out of it just when Poppy wandered in looking for glue sticks. She threw her workout clothes in the wash with the towels then changed for yoga right when Poppy was gathering supplies for the beach. It was weird—not to mention chilly—but how better, in a houseful of penises, to show Poppy that while there was nothing wrong with her body, for a girl it was pretty unusual? But it seemed not to make an impression. Very nearly seven-year-old Poppy’s body looked no more like adult Penn’s than adult Rosie’s when you got right down to it. She was grateful, really, that Poppy didn’t understand. But she was also panicked, really, that Poppy didn’t understand.

It was a torturous evening. It was worse, in fact, than the one it commemorated, Poppy’s first sleepover, its anguished waiting escalating in intensity the longer it went on, proving altogether more painful than Rosie’s quick final labor. The girls started with the baked brie and the Doritos, ignoring Penn’s neat baguette slices and scooping up fancy French cheese with neon orange triangles instead. Rosie, anxious to get on with things already, tried to serve the (such that it was) main course then, but Penn pointed out it was only four thirty, and Poppy whined, “Mom, we have so much to do.” They all four whirled up to her turret while Rosie cursed the stairs: she couldn’t hear what they were doing up there by pressing her ear to the door at the bottom of them. Lots of giggling. Lots of high-pitched joy. They came down and watched The Sound of Music. They wanted to make clothes out of the curtains, but Penn steered them toward marshmallow monsters—Poppy’s chosen craft—instead. More marshmallows turned into snacks than into monsters. Then Poppy opened presents, and then she consented to dinner: the sandwiches and sushi. Rigel and Orion did a magic show with a set they’d gotten several birthdays ago, supplemented by an actual hacksaw and a chocolate rabbit they did indeed saw in half and manage to reattach by licking the edges until they were sufficiently sticky. The girls giggled. Roo and Ben stayed in their basement and pretended none of the rest of them existed. Penn blew up a bunch of balloons for a lawless, anarchic game of balloon tag. And Rosie fretted.

They called the older boys up for singing, cake, and ice cream. It was her first all-girls birthday, and Rosie was pleasantly surprised to see them actually sit and eat, quietly if not neatly, which would have been nice except she still had her own brood to contend with. Rigel balanced a piece of cake on the top hat Orion was wearing, which slid off onto Roo’s plate, which splattered ice cream onto Rigel’s present: orange knit party hats that looked to Rosie like yarmulkes. The twins held each other’s necks in the crooks of their elbows and rolled around on the kitchen floor for a bit, spreading dropped cake and ice cream into every corner and whipping Jupiter into a frenzy of barking and alarm. Rosie envied the dog, for whom it was socially acceptable to walk around whining ceaselessly when she was feeling anxious.

When the girls started yawning, Penn lightly suggested it might be time to start thinking about getting ready for bed. Rosie wasn’t ready yet. She felt like she was breathing very quickly all of a sudden. She tried to look nonchalant while the girls trundled upstairs. Then she raced for the turret steps like an about-to-be-sawed-in-half chocolate rabbit. She climbed the stairs as quietly as she could, stopping halfway up, like Christopher Robin, trying not to pant and give herself away. She heard bags unzipping, kicked-off shoes whacking into the molding, clothes being shed, soft exclamation over Kim’s Seattle Storm pajamas and Natalie’s slippers shaped like bear feet. She strained but could not hear whether or not underwear was being removed. Why couldn’t underpants be louder? She heard Poppy’s dresser drawers open and shut, open and shut again. Suddenly, Poppy was walking back toward the stairs.