Alien Mother

Because she was part human. Ripley and the queen were cloned from DNA found mixed together, and they weren`t perfect clones. They accidentally gave the queen a mammal reproductive system along with her old one, just as they gave Ripley acid blood and a different muscular structure (as you can see from her increased strength). As the queen became pregnant with the newborn, she stopped laying eggs, but they didn`t know what was happening to her, because apart from being a Xenomorph, she was a new kind of Xenomorph that was even xeno-er to them.

ok but how did she get pregnant the human way then, if they say she had a human reproductive system i only know one that works.

Well she was hermafrodite (damned spelling for latin words in english mixed with greeke gaaaaaaaah).

but that makes no sense why she just changed from egg to womb. there was no reason for her to change, nothing brought the catalist. to give birth it would need a male. if it was hermaphaditic then it shouldnt have changed at any point. I DONT GET IT! im confused

Well the only explanation i se is that because the mammal reproductive system needs more time to produce a baby than the xeno one needs for producing an egg, they were both working at the same time, but when the developement of the newborn began to take too much energy for the egg laying to continue, it stopped.

Alright, that actually makes sense. Woo! I felt like a confused scientist haha.
You know what's pretty crazy, that mutant alien baby was crazy strong just afte being born. I took off the queen's head with one swipe. It was like FWAPP!

don`t give me that much credit just yet, that`s a theory i came up with right now hehe. Maybe it`s been discussed before and another agreement was made, but until one of th older members explains why it would be different, that`s what i`ll belive.