Hi desidest,
With regard to the wild holly we see around in woods and countryside, at this time of the year, it's the female, mature holly bushes that bear the familiar fruits.
With regard to ornamental garden varieties sold in garden centres, it can be a little more confusing, for example there is one variety named 'Silver queen' which is actually a non fruiting male pland, conversly there is also a female variety named 'Golden king'
A good garden centre or nursery should have male or female varieties labelled so that costomers can select both kinds for cross pollination. Good Luck Tbird+