Cleveland Browns quarterback Josh McCown is sacked by the San Diego Chargers’ Jeremiah Attaochu in October 2015. (Lenny Ignelzi/AP)

Yes, we rightly celebrate Venus and Serena Williams, and, yes, we rightly celebrate Peyton and Eli Manning. But neither set of sports siblings is as remarkable as the Brothers McCown, Josh and Luke.

The Williams girls and the Manning boys have thrived over an athletic lifetime as among the best to play their games. The Brothers McCown have somehow survived over an athletic lifetime despite having the gridiron skill set of a pylon.

Both have been NFL quarterbacks for a long while and both have been, well, not good for a long while.

In a statistical improbability that trumps most statistical improbabilities, Josh and Luke both started on the same NFL Sunday on Dec. 9, 2007, and both lost, then — nearly eight years later – they both started again on the same NFL Sunday, on Sept. 27, 2015. They both lost again and they both threw game-ending interceptions in the final 90 seconds.

Josh, 36, has played NFL games for seven teams while Luke, 34, has played for five teams; the perpetually hapless Buccaneers and the perennially quarterback-challenged Browns are the only NFL franchises to sign the dotted line with both McCowns.

As of this morning, Josh is with the Browns, and Luke is with the Saints.

(Column Intermission I: The Jets’ Ryan Fitzpatrick — no relation to either McCown — is starting at quarterback for his sixth NFL team. In prior stints with the Rams, Bengals, Bills, Titans and Texans, he’s never had a single winning season. But he interviews well, and he’s a smart kid, plus he shows up at all tryouts wearing his Harvard letter jacket.)

Here are some Brothers McCown fun facts, always a great addition to any dinner party:

1. Josh’s career passer rating is 77.4, Luke’s is 70.9; these numbers compare favorably with Ty Detmer at 74.7 and Koy Detmer at 61.2.

2. Josh played one season, in 2010, with the Hartford Colonials of the United Football League and was the league’s highest-rated passer; then again, who couldn’t put up big numbers against the Sacramento Mountain Lions’ secondary?

3. Luke threw nine touchdown passes in his first nine NFL seasons — that’s an average of one per year – and hasn’t thrown a touchdown pass since 2007.

4. In 2008, Josh appeared in two games with the Panthers, for end-of-contest kneel downs against the Falcons and Chiefs; though just 17-35 as a starter, he was 2-0 in that role.

5. In 2011, the 49ers signed Josh on Aug. 17; less than three weeks later — just before the regular season began – they said, “What have we done?” and released him.

6. Luke has appeared in 58 NFL games, 48 as a backup.

(Column Intermission II: I tried to do the right thing in the offseason, no longer calling my hometown team the “Washington R-dsk-ns” but rather the “Washington Snyders.” But it turns out “Snyder” is an offensive term used to disparage, denigrate and desecrate greedy, tone-deaf, out-of-touch billionaire businessmen. So, from this point on, I simply will refer to “The Washington NFL team based in Greater Landover, Md.”)

Luke’s everlasting backup status, semi-miraculously, landed him a starring role in a national TV ad campaign this year – for Verizon Wireless, in which he explains that most of Verizon’s towers have backup generators and utters the line, “I bet if they just had the chance, some of those backups would really shine.”

Imagine his horror when the Saints’ Drew Brees was sidelined last month and Luke became the team’s No. 1 quarterback.

“Coach, I can’t start Sunday — I’ll lose my commercial deal. I’m A BACKUP.”

Perhaps the greatest symbolic moment of the Brothers McCown’s checkered NFL careers came in July 2008. Right after the Dolphins signed Josh and just before training camp began, Josh needed six stitches in his throwing hand’s index finger, as a result of a wood-chopping mishap.

The accident occurred when Josh was holding firewood while Luke was chopping it.

Frankly — and this might go to the heart of the Brothers McCown’s QB struggles — if Luke can’t tell the difference between his brother’s hand and a piece of firewood, what are the chances he can tell the difference between a wide receiver and a defensive back?

Ask The Slouch

Q. As a famous alum and noted sports authority, will you be consulted regarding the selection of the next Maryland football head coach? (G. Dean Smith; Mequon, Wis.)

A. Actually, if they overlook my outstanding on-campus parking tickets, I’d be willing to take a shot at the job.

Q. Should Sepp Blatter step down? (Mark Leavitt; Spokane, Wash.)

A. I truly believe most FIFA and NFL problems would be solved if Sepp Blatter and Roger Goodell swapped posts.

Q. Undoubtedly disappointed that you had been bypassed again for a $625,000 MacArthur Foundation genius grant, how did you mask your feelings? (Howard Walderman; Rockville, Md.)

A. One ice cold Yuengling at a time.

Q. Do NFL game officials count against the Seahawks’ salary cap number? (Pete Hallock; Sagle, Idaho)

A. Pay the man, Shirley.

You, too, can enter the $1.25 Ask The Slouch Cash Giveaway. Just email asktheslouch@aol.com and, if your question is used, you win $1.25 in cash!