“Formed" [Vayitzer]5Vayitzer is written with the letter yod appearing twice, although in verse 19, regarding the creation of the animals, the same word is spelled with just one yod. – there were two acts of formation [involved in the creation of humanity], the formation of man and the formation of woman, a formation of seven [months] and a formation of nine [months].6According to the Midrash, some babies are born after a gestation of seven months, others after nine months.
A fetus that developed in the womb for eight months was considered unviable. Rav Huna said: If it was formed according to the seven [month process], and then born during the eighth or ninth [month], it can live. But if it was formed according to the nine [month process] and born during the eighth, it will not live, all the more so [if it is born] during the seventh. They asked before Rabbi Abahu: From where is it derived that a fetus born during the seventh month can survive, [but one born during the eighth cannot]?
He said to them: From your own [language] I will prove it to you: Zeta7This is the name of the seventh letter of the ancient Greek alphabet, and also means ‘live.’ – epta8It means seven. Seven thus indicates life.; eta9The name of the eighth Greek letter, also meaning “dying.” – okto.10It means eight. Eight thus indicates death.