First you must craft a knife:
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Then, to make a human clone, right click, be an emo, and cut your self(Be warned it takes out 19/20 of your health, if you are not on full health you will die!)
Or to clone an animal/mob attack them with it(You cannot clone Snowmen or enderdragons(Though I could change that...)
Then craft a test tube:
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And add the blood covered knife to the test tube:
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You will automatically throw away the knife. Like, who wants a knife covered in creeper blood? It might explode...
Then, craft a centrifuge:
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And place in it up to four test tubes.
Then power it with fuel(To spin completely it uses up 8 coal)
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Now craft a needle:
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Then grab your now Separated Blood Sample and add it to the needle to fill the needle with the genomic DNA.
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Then inject the needle into an egg with some bonemeal(to make it grow quicker).
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Then, if you made a human egg, keep on going, otherwise, well done, you have just made a mob spawner egg! Yay!

If you made a human egg, place it on the ground(See, bonemeal does make this grow faster!)
Now, introduce an electrical(redstone) current into the egg to start the growing process.