Timothy Chad Hutchinson and
Jeremy Hutchinson are the sons of former Arkansas Senator
(Young) Tim Hutchinson and the nephews of current Arkansas Governor
Asa Hutchinson. Both are 45 and have served in the Arkansas legislature, Tim Jr. from 2005 to 2011 in the state house, and Jeremy from state house from 2000 to 2007, and again from the state senate from 2011 to 2018...when he was indicted by a federal grand jury on 12 wire and tax fraud charges. I don't think Jeremy is getting elected against any time soon. Given how dynastic Arkansas politics are I could see Tim Jr. getting into the Governors mansion or in the Senate.
I keep forgetting that
Brian Schatz is a twin. Given he's only 46, he could either get picked as a VP candidate, get elected from there, or be elected in his own right at any time from now to the next 30 years. According to wikipedia, his brother Steve, "
runs the Hawaii Department of Education's Office of Strategic Reform". Whatever that means.
Looking into an even more hypothetical future, astronaut, husband of Gabby Giffords, and gun violence advocate
Mark Kelly is 55 years old right now, and is running for Senator of Arizona in the 2020 special election (the election for the full 6 year term will be in 2022). If he wins both, and proves a good track record, he could run in 2028 with 8 years under his belt at the slightly old age of 64. Of course this would require a
lot of ifs, not the least of which is him getting elected in the first place, and his wife's health. Also, to my knowledge, his twin brother and fellow astronaut
Scott Kelly has expressed little interesting in running for anything.
Going even farther out there, you have George W. Bush's fraternal twin daughters,
Barbara Pierce Bush and
Jenna Bush Hager. Given their political heterodoxies, and the what the Bush family name means to some people, I don't know if they'd have a shot.