Aliens reproduce by infesting other species. The Queen lays eggs. Eggs carry facehuggers, which latch on to the head of the victim. A long, thin tube plants an Alien embryo in the host's guts, and the facehugger falls off and dies. The second stage Alien, the embryo, grows and feeds off its host until it grows beyond what the host can offer. At this point, it emerges from the chest cavity of the host; for this we call it the Chestburster. This form is extremely vulnerable, but it goes into cocoon quickly. When it emerges from the cocoon, it is the third and final stage: an adult Alien.
The Queen is different from terrestrial insects in that she does not need a male to fertilize her eggs; she is the ultimate in alien feminism. The xenomorph life-cycle does not need males, although all Aliens except the Queen are understood to be male. The Queen is the smartest member of the hive, and the IQ of the average Queen has been estimated at around 240 or so. The Queen maintains complete control of the hive at all times. Any alien which is not the Queen must bow to her will. She also has the ability to "see without seeing", meaning some rudimentary form of telepathy, or far-sighted awareness. This is due to the hive matrix, a black, ropy resinous material. It is created by the Queen and her children; she can see any who walk among it and send drones to attack.
Drones are responsible for keeping the hive in hosts. They attack and drag off lifeforms that the facehuggers will impregnate. They have the average intelligence of a dog. In the absence of a Queen, a drone can become a Queen.
There are other classes of Aliens, and they vary between which branch of the fandom you're going with. In the movies, you have the Royal Guard, seen as the Queen's companions while Ripley rescues Newt. These are the ones she waves off when Ripley threatens the eggs. The Royal Guard are analogous to Praetorians in the video games, which are proto-Queens. (Interestingly enough, Praetorian comes from praetor, the word for a Roman official who was ALMOST a consul.)
There are also Runners and Warriors. Runners are scout Aliens, made from animals. The Alien in Alien3 was a Runner. Warriors are born from Marine hosts. Their bodies are harder and their constitution is firmer, as they will continue to protect the hive even after serious structural damage.
With that being a brief run-down on Aliens, there is ONE case I know of where one could dictate gender and sexuality in the Alien drones. That one time is in Alien Resurrection.
AR is a powerful movie anyway, but there is a time when Ripley is being taken to the Queen to witness the birth of their child (a virgin birth, I might add.) Below, is the scene I am talking about. A drone carries Ripley.
Pretty sexy, huh? Ripley certainly doesn't look like she's complaining. And in fact, Sigourney Weaver has admitted to thinking the Alien is sexy. (I have documentation :D) Other than this one scene, the Aliens have no evident sexuality, although they are loaded with symbolic sexuality.
And with that, I am a total nerd :B