Superfetation is the simultaneous occurrence of more than one stage of developing offspring in the same animal.
Fertilisation or fertilization, also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a zygote and initiate its development into a new individual organism or offspring. While processes such as insemination or pollination, which happen before the fusion of gametes, are also sometimes informally referred to as fertilisation, these are technically separate processes. The cycle of fertilisation and development of new individuals is called sexual reproduction. During double fertilisation in angiosperms, the haploid male gamete combines with two haploid polar nuclei to form a triploid primary endosperm nucleus by the process of vegetative fertilisation.
In vitro fertilisation (IVF) is a process of fertilisation where an egg is combined with sperm in vitro. The process involves monitoring and stimulating a woman's ovulatory process, removing an ovum or ova from their ovaries and letting a man's sperm fertilise them in a culture medium in a laboratory. After the fertilised egg (zygote) undergoes embryo culture for 2–6 days, it is transferred by catheter into the uterus, with the intention of establishing a successful pregnancy.
Amphitryon, in Greek mythology, was a son of Alcaeus, king of Tiryns in Argolis. His mother was named either Astydameia, the daughter of Pelops and Hippodamia, or Laonome, daughter of Guneus, or else Hipponome, daughter of Menoeceus. Amphitryon was the brother of Anaxo, and Perimede, wife of Licymnius. He was a husband of Alcmene, Electryon's daughter, and stepfather of the Greek hero Heracles.
Twins are two offspring produced by the same pregnancy. Twins can be either monozygotic ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic, meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In very rare cases twins can have the same mother and different fathers.
A multiple birth is the culmination of one multiple pregnancy, where in the mother gives birth to two or more babies. A term most applicable to vertebrate species, multiple births occur in most kinds of mammals, with varying frequencies. Such births are often named according to the number of offspring, as in twins and triplets. In non-humans, the whole group may also be referred to as a litter, and multiple births may be more common than single births. Multiple births in humans are the exception and can be exceptionally rare in the largest mammals.
The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that makes pregnancy possible. The ovarian cycle controls the production and release of eggs and the cyclic release of estrogen and progesterone. The uterine cycle governs the preparation and maintenance of the lining of the uterus (womb) to receive an embryo. These cycles are concurrent and coordinated, normally last between 21 and 35 days, with a median length of 28 days, and continue for about 30–45 years.
Artificial insemination is the deliberate introduction of sperm into a female's cervix or uterine cavity for the purpose of achieving a pregnancy through in vivo fertilization by means other than sexual intercourse. It is a fertility treatment for humans, and is a common practice in animal breeding, including dairy cattle and pigs.
The female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. The human female reproductive system is immature at birth and develops to maturity at puberty to be able to produce gametes, and to carry a fetus to full term. The internal sex organs are the vagina, uterus, fallopian tubes, and ovaries. The female reproductive tract includes the vagina, uterus, and fallopian tubes and is prone to infections. The vagina allows for sexual intercourse and childbirth, and is connected to the uterus at the cervix. The uterus or womb accommodates the embryo, which develops into the fetus. The uterus also produces secretions, which help the transit of sperm to the fallopian tubes, where sperm fertilize ova produced by the ovaries. The external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris, and vaginal opening.
Assisted reproductive technology (ART) includes medical procedures used primarily to address infertility. This subject involves procedures such as in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), cryopreservation of gametes or embryos, and/or the use of fertility medication. When used to address infertility, ART may also be referred to as fertility treatment. ART mainly belongs to the field of reproductive endocrinology and infertility. Some forms of ART may be used with regard to fertile couples for genetic purpose. ART may also be used in surrogacy arrangements, although not all surrogacy arrangements involve ART. The existence of sterility will not always require ART to be the first option to consider, as there are occasions when its cause is a mild disorder that can be solved with more conventional treatments or with behaviors based on promoting health and reproductive habits.
Embryo transfer refers to a step in the process of assisted reproduction in which embryos are placed into the uterus of a female with the intent to establish a pregnancy. This technique - which is often used in connection with in vitro fertilization (IVF) - may be used in humans or in other animals, in which situations and goals may vary.
Third-party reproduction or donor-assisted reproduction is any human reproduction in which DNA or gestation is provided by a third party or donor other than the one or two parents who will raise the resulting child. This goes beyond the traditional father–mother model, and the third party's involvement is limited to the reproductive process and does not extend into the raising of the child. Third-party reproduction is used by couples unable to reproduce by traditional means, by same-sex couples, and by men and women without a partner. Where donor gametes are provided by a donor, the donor will be a biological parent of the resulting child, but in third party reproduction, he or she will not be the caring parent.
Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes (ova) and males producing smaller gametes (sperm). In nearly all animal species, offspring are carried by the female until birth, but in fish of the family Syngnathidae, males perform that function.
Human reproduction is sexual reproduction that results in human fertilization to produce a human offspring. It typically involves sexual intercourse between a sexually mature human male and female. During sexual intercourse, the interaction between the male and female reproductive systems results in fertilization of the ovum by the sperm to form a zygote. While normal cells contain 46 chromosomes, gamete cells only contain 23 single chromosomes, and it is when these two cells merge into one zygote cell that genetic recombination occurs and the new zygote contains 23 chromosomes from each parent, giving it 46 chromosomes. The zygote then undergoes a defined development process that is known as human embryogenesis, and this starts the typical 9-month gestation period that is followed by childbirth. The fertilization of the ovum may be achieved by artificial insemination methods, which do not involve sexual intercourse. Assisted reproductive technology also exists.
Controversy over the beginning of pregnancy occurs in different contexts, particularly as it is discussed within the debate of abortion in the United States. Because an abortion is defined as ending an established pregnancy, rather than as destroying a fertilized egg, depending on when pregnancy is considered to begin, some methods of birth control as well as some methods of infertility treatment might be classified as causing abortions.
In genetics, a non-paternity event is the situation in which someone who is presumed to be an individual's father is not in fact the biological father. This presumption of NPE is a subset of a misattributed parentage experience (MPE) which may be on the part of the individual, the parents, or the attending midwife, physician or nurse. An NPE may result from sperm donation, undisclosed adoption, heteropaternal superfecundation, promiscuity, paternity fraud, or sexual assault, as well as medical mistakes, for example, mixups during procedures such as in vitro fertilization and artificial insemination. Where there is uncertainty, the most reliable technique for establishing paternity is genetic testing; however, there is still a risk of error due to the potential for gene mutations or scoring errors.
Pregnancy rate is the success rate for getting pregnant. It is the percentage of all attempts that leads to pregnancy, with attempts generally referring to menstrual cycles where insemination or any artificial equivalent is used, which may be simple artificial insemination (AI) or AI with additional in vitro fertilization (IVF).
Religious response to assisted reproductive technology deals with the new challenges for traditional social and religious communities raised by modern assisted reproductive technology. Because many religious communities have strong opinions and religious legislation regarding marriage, sex and reproduction, modern fertility technology has forced religions to respond.
Partner-assisted reproduction, reception of oocytes from partner (ROPA), reciprocal IVF,shared motherhood, partner IVF or co-IVF is a method of family building that is used by couples who both possess female reproductive organs. The method uses in vitro fertilization (IVF), a method that means eggs are removed from the ovaries, fertilized in a laboratory, and then one or more of the resulting embryos are placed in the uterus to hopefully create a pregnancy. Reciprocal IVF differs from standard IVF in that two partners are involved: the eggs are taken from one partner, and the other partner carries the pregnancy. In this way, the process is mechanically identical to IVF with egg donation. Reciprocal IVF offers the highest chance for pregnancy and a lower chance of a multiple births.
Lesbian, gay, bisexual, and transgender people people wishing to have children may use assisted reproductive technology. In recent decades, developmental biologists have been researching and developing techniques to facilitate same-sex reproduction.
