Do lemon trees need opposite gender to produce fruit?

Question:A customer at the store told me that lemon trees need both a male and female plant to produce fruit. Is this true? What other common fruit trees need opposite gender pollination to produce fruit.

Thanks

Answers:
No you don't need opposite gender for Citrus. You do for some nut trees, and you do for Kiwi fruit.What that customer may have been told, some varities do better with another variety close by.I grow a fruit called a Fejoa, and I have two varities close together.I get better and bigger fruit.