fetus

An unborn or unhatched vertebrate showing signs of the mature animal.

Several feti were removed from every rats' uterus, stripped of their membranes and allowed to lie in the peritoneal cavity connected to the placenta by the umbilical cord and with the placenta still attached to the uterine wall.

A human embryo after the eighth week of gestation.

The sequence is: molecules in reproductive systems, then gametes, zygotes, morulas, blastocysts, and then fetuses.

Though scientists do not know how stress affects gestation, Fukuda theorizes that the vulnerability of Y-bearing sperm cells, male embryos and/or male fetuses to stress is why “subtle significant changes in sex ratios” occur. […] The factors that filter out who “gets through” from conception to birth include chromosomal or genetic abnormalities of the fetus or the mother’s stress response to changes in her environment, Catalano said.

A neonate.

The real essence of that or any other sort of substances, it is evident, we know not; and therefore are so undetermined in our nominal essences, which we make ourselves, that, if several men were to be asked concerning some oddly-shaped fœtus, as soon as born, whether it were a man or no, it is past doubt one should meet with different answers.