What causes a fetus to become either male or female?

Question

I've heard male babies are dependent on the father's sperm, not on the mother, is that true?

Answer 1

Male babies and female babies are dependent of fathers sperm.

chromosome of father-XY

chromosome of mother-XX

While fertilization if x chromosome of father combines with x chromosome of mother then it will be a female child.

If y of father and x of mother combines then the baby will be male

Answer 2

the sperm carries and X or a Y, the egg will always be an X( males are XY females XX.

but specifically theres a gene on the Y chromosome that acts as a trigger for development of male sexual traits this gene is called the SRY gene.

Answer 3

All babies are dependent on the father's sperm. He holds half the genetic material. As to the mechanism of how the chromosomes arrange themselves in Xs and Ys, someone else can probably answer that.

Answer 4

Yes, the s*x of a child depends on the sperm of the father. If it gets a X chromosome from the father, it will be a girl. If it gets a Y chromosome, it will be a boy.

Answer 5

Yes, it's true.

Women are XX, men are XY.

The X or the Y from the male is the determination of the s*x of the child. Women only give the 2 X's, which are female.

Answer 6

Men have an XY chromosome combination and females have an XX combination.  The mother can only contribute an X chromosome so essentially the father does determine the s*x of the child.  If he contributes an X then a girl forms if he contributes a Y then the child will be male.  Sometimes too many chromosomes are passed (XXY, x*x etc.) and genetic abnormalities develop.

Answer 7

The answer is hormones.

We all start out from the same "blank" if you will.  Until a certain fetal age we are all female.  That is why men have nipples.  It is the presence of hormones that causes male babies to be made...and this comes from the "Y" chromosome.