Les and Marianne Boring sat next to each other on the top row of bleachers at Atholton's stadium Saturday, one on each side of the midfield line, appropriate seating because their allegiances were on both ends of the field.

On one side of the field was their oldest daughter, Halley, a senior midfielder at Atholton. On the other side was their youngest daughter Allison, a freshman attack for Reservoir.

"I know one thing: We're going to win and lose this game, and that doesn't happen very often," Les Boring said during the Maryland 2A/1A North Region quarterfinal. "It's Halley's senior year, and it was good to see Allison make the varsity team as a freshman, and now they're playing each other in the playoffs. It's a great way to script it."

Here's how the story played out in the sweltering heat: Halley had a game-high five goals and four assists to power the Raiders to a 17-5 victory over Reservoir, which got one goal from Allison in a season-ending loss. The two girls were embraced by their parents and three brothers, knowing this was the final time they would share the same high school field.

"When Halley scored I was like, "Yeah, that's my big sister,' " said Allison. "She's so much better than me."

"And when Allison scored I was happy, but then I'd ask our defense how'd they let it happen," said Halley.

Allison Boring attends Reservoir because the family's home is in the district created when the new school opened in 2002. Her sister was allowed to remain at Atholton because she was there before Reservoir opened.

Though the Borings' story is particularly uncommon, there are many siblings making an impact as postseason play began Friday, most for the same school.

River Hill's Jackie and Matt Davidson have spent countless hours on the tennis court playing against their parents, Mark and Joanna, so it was no surprise when the duo formed a mixed doubles team and finished second at the county championships Saturday. They will play in this weekend's District III tournament.

"In doubles, what's most important is that you have two players who complement each other very well and know each other," said River Hill Coach Matt Graves. "And Jackie and Matt live together. What could be better than that?"

"I thought it would be pretty cool since we've both been playing together for such a long time, and we have a close relationship," said Jackie, a senior.

"She's great around the baseline, and I play pretty well around the net, and we just make a good team," said Matt, a sophomore. "We're not like the normal brother and sister who are always fighting. We like hanging out, and we have a lot of the same friends, and I don't think we could be a good team if we didn't get along as well as we do."

As the Davidsons look to win the school's first state tennis title in four years, brothers Mike and Josh Bogdanor hope to lead the Hawks to their first region title on the lacrosse field. But they also know their next loss might mark the final time they play on the same team.

"Having a brother is a really big advantage," said Mike Bogdanor, a junior goalie. "Growing up, I had someone to shoot on me every day in our backyard and play lacrosse with. Josh gets a lot of credit for helping me be able to start on varsity."

Josh, a senior defenseman, realizes the time they have to play on the same team is running out. Josh plans to play at the University of Maryland Baltimore County and knows that is not one of the schools his younger brother is interested in attending.

"I'm trying not to think about that until I have to because I know this is probably it," Josh said. "I'm just glad I got the chance to play with him -- and to me, that's the best part about playing lacrosse at River Hill -- because not many brothers get to play on the same varsity team together, so I think we're really lucky we got to experience this."

Glenelg's Ashley and Aly Blum have spent the past three years playing on the varsity girls' lacrosse team, but both acknowledge it is inevitable they will see each other again on the playing field, perhaps wearing different uniforms.

Ashley, a senior goalie, will play next season at Cornell, and Aly, a junior who is one of the county's best defenders, also aspires to play in college.

"It's not that I'm looking forward to playing against my sister, and if it happens, it happens," Ashley said. "When you're in the middle of intense competition, you're focused on what you're doing and [what] the team's doing. Aly's a great defender, and she makes a big difference out there, whether or not she's my sister."

"I just want for each of us to go to a place that we'll be happy," Aly said. "But should we play, I'll be torn because she's my sister, but also I'll have no mercy for the other team."

Atholton's Halley Boring scoops a loose ball as she tries to get away from Reservoir's defense, including sister Allison Boring (12), during Saturday's 2A/1A girls' lacrosse quarterfinals. Below, River Hill's Jackie Davidson and brother Matt play mixed doubles in the Howard County tennis championships Saturday.Marianne and Les Boring, with their youngest son, Bryce, lying between them, watch their daughters, who attend different schools. Above, Halley Boring runs upfield with sister Allison trailing during Atholton's 17-5 win. Below, River Hill's Jackie and Matt Davidson leave the court after losing in the county championships.