Good question :-)) Since 'Helen Corbett' (or Corbet) is not listed as a registered cultivar name on any conifer database I could find, information is scant. One could make the logical assumption that the selection is female.....but no guarantees. A 50-50 chance. 😑

Or just wait for a year or two and see if it produces berries.

But even if it’s female, without a male it won’t fruit will it?

Golly, one never really knows with yews. They are wind pollinated so proximity to another is relative. And then there are those instances where both female and male versions of the same cultivar exist or isolated instances of bisexuality.

ETA: The plant in question is most likely to be Taxus x media 'Helen Corbit'. Again, minimal info available so all my previous observations still apply :-)