Couldn't predators reproduce more like marsupials? Perhaps even one of the pouchless ones like a numbat. But I suppose it really depends on what you consider canon when it comes to the predators. To my knowledge, there have been no actual female predators in the movies, but if you expand it out to the book/comic realm, you have seen them on occassion, showing that appears very human-ish attributes. Outside of the appearance of the females in the books/comics, I don't know how far you can actually take this conversation.
On a side note, I noticed that it was mentioned about the color of the blood and body tempature. The blood, it may just have to do with what chemicals make up their blood, it may be coppor based with something else in it that makes it 'glow' under the conditions present on Earth... or for that, in conditions that allow humans to live (this would explain why it appears a glowing green in places where humans are outside of earth)
Additionally, I wouldn't say that predators are cold-blooded, it could be as simple as they are just considerably colder then what they are looking at, just like you would find with a lot of thermal viewing systems, it constantly has the image color shift to acount for things that are significantly hotter then other objects in an environment.