Three lines of evidence suggest that, instead, sex determination may start shortly after conception: (1) the XY preimplantation embryo usually develops more.
This is because of the presence of the sex-determining region of Chromosomal sex is determined at the time of fertilization;.
"The sex of a baby is determined by its chromosome make-up at conception. An embryo with two X chromosomes will become a girl, while an.
A test has been developed to determine the sex of an embryo from only five weeks old. In the UK current tests can determine sex from 11 weeks.
There are two basic phases of sexual development in mammals: sex determination at fertilization and sex differentiation that is associated with sex determination.