Eddie Jones has insisted he does not care about the specifics of Test rugby's eligibility rules and will pick anyone who qualifies for England.
Gloucester's Willi Heinz has been drawn into England's latest training camp, with the New Zealand-born scrum-half qualifying through his grandmother. Heinz represented New Zealand's under-21s and even played against England for Super Rugby outfit Crusaders in 2014.
World Rugby have extended the residency qualification period to represent a new nation from three to five years to come into effect in 2020, but Jones insisted England will continue to select anyone available -- irrespective of background.
"It's not my job to worry about how they qualify, it's my job to pick players that qualify," Jones said. "I don't care how they qualify, I'll pick them.
"That's the rules we play under. I obey them like any good schoolteacher does."
England face the Barbarians at Twickenham on May 28 and must this week do without those stars still involved in the Premiership and European playoffs.
With no players from Saracens, Exeter, Wasps, Leicester or Northampton, Jones has drafted in a raft of youngsters as England continue long-range preparations for next month's two-Test tour to Argentina.
He added: "Tell me, who is there? I look at everything. You don't think I've done my homework?
"I'm picking the best players available to play for England. I've picked a 19-year-old boy that hasn't played in the Premiership, I've picked two 18-year-olds. I've picked Nathan Earle, who's played half a Premiership game.
"I've picked Nick Isiekwe, that's only played one Premiership game. And you're saying I'm not looking at youth. Are you serious? Wouldn't my record suggest I have?"
Despite vowing to pick players from any available source, Jones insisted he does monitor the number of overseas-born players in England's ranks.
"I'm always balancing that," said Jones. "We've got a training camp in Brighton and we're missing five clubs plus Lions, plus whatever, and you're suggesting I'm not looking at the balance.
"I'm struggling to get numbers to train. We never know when we might need these players. Go back to the 2011 World Cup and Stephen Donald, the fifth-choice number 10 coming through for New Zealand.
"We might get to the final in 2019 and need to find the fifth-choice number nine. Now I know who the fifth-choice number nine potentially is."
Fly-half Jason Woodward has also received his first England call-up, as another New Zealand-born half-back included by boss Jones.
Sale's New Zealand-born wing Denny Solomona represented Samoa in Rugby League, but will tour Argentina with England having already qualified on residency.