The proposal was part of Juncker's deeply personal pitch for the future of Europe in his State of the European Union speech on Wednesday, and could be accomplished without changes to the existing EU treaties.
"If there's a diminution in United Kingdom science, which I'm not predicting there would be, but you have some challenges to overcome to make sure that doesn't happen", Mr. Gates said.
Juncker said the European Union should give credible enlargement possibilities to Western Balkan countries to maintain stability in the region.
As at present, this arrangement will cover all EU countries plus those of the European Economic Area (EEA - Norway, Iceland and Lichtenstein) and Switzerland'.
In the speech, the president painted a bright picture for the future of the EU.
Products of Ireland's agri-food sector are among the EU's most exposed to Brexit, the finance ministry's research showed, led by cereals, fruit and vegetables, nearly 90 per cent of which are exported to the UK.
At the same time, European Union officials argue, past attempts by Paris and Berlin to force a lead on integration, such as by Merkel and then president Nicolas Sarkozy at the height of the euro zone crisis in 2011, failed to gain traction.
The government said a short delay "would give negotiators the flexibility to make progress".
He said trade talks should be opened with Australia and New Zealand - saying that he wanted deals to be struck by the time he leaves office in 2019.
Juncker, 62, said he had despaired of the EU at times but wants Sibiu to offer EU voters something other than Brexit to wake up to, two months before a European Parliament election.
Germany leads among European nations in terms of offshore wind energy growth, though Great Britain has more offshore wind capacity installed. "Accession candidates must give the rule of law, justice and fundamental rights utmost priority", he said.
Mr Juncker said he was "saddened" with the refusal by the ex-communist eastern states to take in refugees arriving in the bloc to help their western and southern peers.
He also said the government was not good enough at overseeing large financial projects, which will add to fears the civil service will not be capable of effectively exercising the powers handed back to Britain from Brussels.