Ok, let's assume that humans are mammals for a moment.
The characteristics of mammals include the following:
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Characteristics of Mammals
Mammals have backbones.
Mammals are warm-blooded.
Mammals breathe with lungs.
Mammal babies are born live.
Mammals have fur or hair.
Mammals nurse their young.
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I've bolded the two important ones. Now, according to
this site,
Quote:
six weeks
the sex organs develop
the embryo now has a full skeletal system
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I'm assuming that the skeletal system includes the backbone, since it's not mentioned anywhere before it. Also,
Quote:
eight weeks
the fetus (Latin for 'little one')is now two inches long
every organ is now in place
the stomach produces digestive juices
the baby's finger and footprints are clearly visible
the child responds to painful stimuli
the infant can make a fist
the kidneys begin to function
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in 8 weeks the organs are in place. Lungs aren't mentioned before this, so let's assume that the lungs are included with the organs. That's 6 weeks until the backbone is developed and 8 weeks until the lungs are in place. 2 whole months before you could even say it's a mammal.