Venus Williams only has 7 major singles titles. 5 at Wimbledon (2000, 2001, 2005, 2007, 2008) and 2 at the US Open (2000 and 2001). You could also mention that they have 13 grad slam doubles titles together (including a career slam).
Kiev is in Ukraine. Hamburg is in Germany. The Klitschkos were born in the former and fight out of the latter. My lord Americans are lost when it comes to the rest of the world.
Wrestling has a bunch of brothers.
In the US, John and Ben Peterson were both Olympic gold and silver medalists. Tom and Terry Brands were both world champs and Tom was an Olympic champ. Dave and Mark Schultz both won gold in the '84 Olympics along with twins Ed and Lou Banach. The Schultz brothers were also both world champions with Mark being a two timer.
The Saitiev brothers from Russia are probably the most prolific wrestling brothers. Buvaisar was a 3x Olympic Champ and 6x world champ. His younger brother Adam was an Olympic Champ and 2x world champ. Adam may have won more had he not been forced to wrestle up a weight class due to his brother.
Please consider Andy and Bruce Irons in the next one of these. They both shook pro surfing in different ways, and although that may not be considered as popular of a sport as, wait. . .cricket? I wouldn't put them above the Harbaughs, but come on, cricket?! Rest in Peace Andy, and keep shredding Brucy!! You deserve to be on this list! Cricket. . . ugh.
The Chappells had another brother, Trevor, who also played international cricket for Australia. And their grandfather, Vic Richardson was a famous cricketer as well.