The CGI module should use '&' to separate parameters in query strings UNLESS you're using the -newstyle_urls pragma. So you here's how to cheat if it is on and you don't want to take -newstyle_urls out of the use statement:

my $q = CGI->new(%parameters);
$CGI::USE_PARAM_SEMICOLONS = 0;
print $q->query_string;
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