Who does the child come from, the father or mother?
The Talmud states that there are three partners in a child, Hashem, the father and the mother. The white parts of the child come from the father, while the red parts come from the mother. The white parts include the sinews, bones, and nails, brain, the white of the eye. The red part includes the skin, flesh, hair, the back part of the eye.
Sources that state that the child is mainly from the sperm of male: The main body of a child is from the drop of the male. He refines the child so the waste is expelled outside, and from this refinement comes the child. The job of the mother is to merely develop this drop of the father and form it into limbs and a human face.
Sources that state that the child is mainly from the female: The main seeding of the child, and his development, is from the drop of the mother, as from her comes the flesh of the child. The function of the male drop is simply to refine the drop of the female, that the child develops from the choicest of her seed. This is explained in the medical books as follows: The mother gives off the seed, and the seed of the father simply fertilizes and catalyzes it, similar to a catalyst turning milk into cheese. The seed of the father refines the seed of the mother to make it congeal and make from it a child.
Answering the contradiction:
The above compilation of sources projects a contradiction as to which parent is the one mainly responsible for the child’s existence and from whose seed is the child mainly created from. The Talmud suggests that both share in the development and existence of the body of the child, and both of their seeds are a component of the child’s body. From the other sources however it is evident that it is either the fathers seed which creates the entire child and the mothers seed is simply there to develop it, or that it is the mothers seed which creates the entire child and the fathers seed is simply there to refine it. Seemingly, one must answer as follows: The main internal parts of the body, including the body’s skeletal structure and neurological system, are developed from the father’s seed, and from this respect the seed of the mother is simply there to help develop it. However, the main external parts of the body, including the skin flesh and circulatory system, are developed from the seed of the mother and from this respect the seed of the father is simply there to help develop it. Thus both the father and mother contain a portion in the part of the body of the child which was developed from their specific seed, while the other part which was developed from the seed of their partner they helped to refine and develop. Vetzaruch Iyun, Vehashem Yair Es Eiyneiynu!
The science and biology behind an embryo’s development and conception due to fertilization:
The following is the current scientific and medical understanding of how a fetus is developed as result of intercourse, or fertilization. This is universally taught in classes of biology, and much of it is scientifically proven under microscopic observation.
Cells and chromosomes of the human body: The human body is made up of cells, of which each cell is made up of 46 chromosomes. In detail, each cell contains two sets of chromosome coils, with 23 chromosomes in each set. The two sets of chromosome strings in each cell are attached together like a spring, for a total of 46 chromosomes in each cell.
The X and Y sets of chromosome strings-Male versus Female: There exists two types of string containing 23 chromosomes. One of them is known as the X set of chromosomes while the other is known as the Y set of chromosomes. The X set of chromosomes is known as the female chromosome while the Y is known as the male chromosome. The letters represent the shapes of the chromosome. Males have an X and Y set of 23 chromosomes in each cell, while female have a set of 23 X and X chromosomes.
The chromosomes found in a reproductive cell-sperm and egg: The reproductive cells of a man and woman contain only one of the sets of 23 chromosomes, as opposed to the normal 46 chromosomes contained in a regular cell. When the 23 chromosomes of the male’s reproductive cell [i.e. sperm] unites with the 23 chromosomes of the female’s reproductive cell [i.e. the egg] it creates a whole cell and is the start of a pregnancy.
Gender determination: The female reproductive cells are always an X while the male reproductive cells contain either an X set or a Y set. Some sperm cells are an X cell while others a Y cell. If an X sperm cell reaches the egg, the embryo will develop into a girl. If the Y sperm cell reaches an egg, it will develop into a boy. Interestingly, the Y sperm cell which is a male is always dominant over the X egg cell of the female. The Y sperm cell does not dominate over every aspect of the embryo or female X egg cell, but only over the gender organs. However, hair color, and many other aspects can be contributed from the female X egg cell. It is possible that a single ejaculation will have many more Y sperm cells than X sperm cells, and hence chances of having a boy are much higher. It is likewise possible to have the opposite, that a single ejaculation will have many more X sperm cells than Y sperm cells, and hence chances of having a girl are much higher. This is affected by diet, stress, and is also hereditary. [Thus, a man with many more sisters than brothers will likely have many girls.] The Y sperm cells are quicker and faster in reaching the egg than the X sperm cell, and this is one advantage that they have in affecting gender determination in which indeed there are more males than females born in the world each year. The X sperm cell however is more durable in face of stress, in contrast to the Y sperm cell which more easily dies, and thus often the gender of the child is a female and not a male despite the speed advantage of the Y sperm cell. Multiple ejaculations will increase chances of having a male, as there are now more fast Y sperm cells swimming to the egg. When a woman is aroused, her body naturally tries to assist the Y sperm cells to reach the egg versus the X sperm cells. [Thus, a woman’s body naturally accelerates the male sperm cell for the sake of having a male child.] With that said, as of date, there exists no scientific way of guaranteeing gender selection other than IVF.
Words of Chazal which correspond to the above science:
Chazal teach us that boys relate more to the mother. They state that if a woman gives seed first then she has a male child. Likewise, Chazal state that the sons are similar to the mother’s brothers. One can suggest that when Chazal stated that Isha Mazria Techila Yoledes Zachar it means that when she is aroused she sends off her Chesed aspects which “select” the Y sperm cell to enter the egg. Now, although the Y is dominant in the male gender organ formation, the woman’s X sperm cell contributes many of the other aspects, and hence in essence a boy’s body and nature is more the result of the women’s X chromosome than the Y chromosome which is only there for gender selection. However, if the man is Mazria Techila, then the woman’s body is not yet aroused enough to fight for the Y sperm cell, and hence it is more possible that the child will be a female, as the Y sperm of a man is only more popular and stronger at specific times. Now, when the X sperm cell reaches the egg, it is dominant over the woman’s X egg cell and hence the child is more derived from the father sperm.
D. The contribution of the parents to the soul of the child:
Both the husband and wife each independently provide vital parts of the soul garments for the child. One provides the child with an Or Makif while the other provides the child with an Or Penimi. While all agree that it is the Or Makif which is of greatest importance for the child, it is disputed as to which parent provides the Or Makif, the mother, or the father. Practically, Admur concludes that it is the father who provides the Or Makif and the mother who provides the Or Penimi.______________________________________________________
 Niddah 31a
 Torah Or Bereishis p. 8 “From the father comes one drop which includes the son’s entire body”; Parshas Toldos p. 34; Torah Or Shemos p. 107, 108
 Torah Or Parshas Toldos p. 34
 Torah Or Bereishis p. 8, 11; Shemos p. 108; Terumah 159
 Torah Or Shemos 1st Mamar p. 9; Likkutei Torah Chukas p. 126 that so is written in Sifrei Refua; Shir Hashirim p. 9
 Torah Or Shemos 1st Mamar p. 9; Likkutei Torah Chukas p. 126; Shir Hashirim p. 9
 Likkutei Torah Chukas p. 126; Shir Hashirim p. 9
 Basal Body temperature of the female also plays a role. A woman’s temperature will drop just before ovulation. “If a couple plans to have a boy, the best time for copulation is within the fertile window so that the Y chromosome can reach the egg before the X chromosome. On the contrary, a baby girl can be made by having intercourse one to two days prior to a woman’s fertile window that would allow the X chromosome to reach the egg first.”
 Brachos 60a; Niddah 31a; Midrash Raba Tazria 14
 Bava Basra 108; Bava Kama 110a; See Menoras Hamaro Ner Gimel Kelal Vav 2:3
 Likkutei Torah of Arizal Ta’amei Hamitzvos Parshas Bereishis 15; Sha’ar Hagilgulim Hakdama 10; Siddur Arizal of Rav Shabsi 2 Seder Has’chiva 42; Siddur Arizal of Rav Yaakov Kopul Mitzvah Periyah Verivya p. 112
 Sha’ar Hagilgulim ibid and Siddur Arizal of Rav Shabsi ibid writes that the father provides the child with an Or Makif while the mother provides the child with an Or Penimi. However, Siddur Arizal of Rav Yaakov Kopul ibid writes to the contrary that the mother provides the child with an Or Makif while the father provides the child with an Or Penimi; Siddur Ya’avetz Mosach Hashabbos Mitos Kesef 7 Chulya Gimel 15; See Sheyikadesh Atzmo 14:7 footnote 10 in length
 Sha’ar Hagilgulim ibid and Siddur Arizal of Rav Shabsi ibid and Siddur Ya’avetz ibid, writes that the father provides the child with an Or Makif while the mother provides the child with an Or Penimi. However, Siddur Arizal of Rav Yaakov Kopul ibid writes to the contrary that the mother provides the child with an Or Makif while the father provides the child with an Or Penimi
 Ma’amarei Admur Hazakein p. 151 “Lehavin Inyan Zivug Haneshamos” in name of Mekubalim; See Sefer Ha’erechin Chabad Erech Av