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Genesis of twins, , , , + Imonozygotic twins (syn. identical, uniovulvar), + Dizygotic twins (syn: fraternal, binovular, , SP) cee & > eggs, I sperm 2 sperms, , , , Same, , placenta J ene, , placentas, , FP Scparatc, amniotic, , , , On rare occasion, the following, possibilities may occur, + If the division takes place within 72 hour, , fertilization the resulting embryos will have two separate, placenta, chorions and amnions (D/D), , , , + If the division takes place between the 4" and 8" day, after the formation of inner cell mass when chorion has, already developed diamniotic monochorionic twins, develop (D/M), , + If the division after 8" day of fertilization, when the, , amniotic cavity has already formed, a monoamniotic, monochorionic twins develop (M/M), , Page 6