You're in luck. Ginkgo (Ginkgo biloba) has separate male and female trees, so purchasing a male cultivar is the best way to avoid the smelly and messy-fruiting female ginkgo. Avoid purchasing a seedling ginkgo; there's no way to know what sex the mature tree will become. Instead, purchase a named male cultivar that has been grafted onto a seedling rootstock or propagated from stem cuttings. Male cultivars to look for include 'Autumn Gold', 'Fairmount', 'PNI 2720' (Princeton Sentry), 'Saratoga', and 'Shangri-la'.