Sex Determination (Nursing)

00:01 So how is the genetic sex of a fetus or eventual infant determined/ of the 46 chromosomes and the fertilized eggs only two of them are sex chromosomes.

00:15 The rest of them we refer to them as autosomes are autosomal chromosomes.

00:21 The two sex chromosomes include the X chromosome, which is the larger of the two, and then the Y chromosome, which is actually quite small.

00:31 Females contain two X chromosomes where each ovum always has an X chromosome.

00:41 And males, you're going to have X and Y chromosomes so in the male body 50% of the sperm are going to contain X chromosomes and 50% of the sperm are going to contain Y chromosomes.

00:57 So if fertilizing sperm delivers an X to the fertilized eggs, then it will contain an X X and the embryo will develop ovaries.

01:08 However, if the fertilizing sperm delivers a Y chromosome, then the fertilized egg will contain X Y and the embryo will develop testes.

01:20 The development of testes is caused by the SRY gene, which is a master switch on the Y chromosome.

01:29 It's important for the initiation of testes development and maleness.

01:35 Because it is the father or the sperm that will deliver the X or the Y and because the ovum always contains X chromosomes.

01:46 It is the father that determines the sex of a child during conception.