It is an interesting discussion. In all airlines i flew in the decision to reject a take off was and is only up to the captain. However back in a previous airline when we switched from our in house SOP to Airbus SOPs, which included the FO starting engines, taxying and parking the aircraft (if the parking system allowed it), the question came up if the FO should have the authority to reject a take off as well. Some trainers tested that in the spare time in normal simulators, a few go/no-go decisions by the Captain and then the same for the FO. One thing stood out, that every FO rejected a take off for a sudden emergency electric configuration which ended with a high speed runway excursion. Not necessarily very scientific, but it put that topic to rest.
Personally i am undecided. We trust FOs with nearly everything else in many airlines, but not with the go / no-go decision.