The same hormones that control ovulation in women stimulate the release of testosterone in men. Testosterone is the hormone responsible for producing sperm. Sperm production starts in the testicles, the two glands contained in the scrotal sac beneath the penis. The testicles hang outside the body because they are sensitive to temperature. To produce healthy sperm efficiently they have to stay at a balmy 34 degrees C. This is about three degrees cooler than normal body temperature. Once the man’s sperm is created, it’s stored in each testicle in the epididymis, a six-metre long coiled tube. Just before ejaculation the sperm is scooped up and mixed with semen. During ejaculation the sperm pass through the sperm ducts and mix with fluids produced by the glands. The fluids provide the sperm cells with nutrients. The mixture of sperm and fluids is called semen. This passes out of the penis. Deanna also writes a series of books for middle grade readers, including JINNIE WISHMAKER, MARCUS MENDER, and ELEKTRA CHAOS. Knudtson J, McLaughlin JE. 2019. Female reproductive endocrinology. MSD Manual, Professional Version. www.msdmanuals.com Opens a new window [Accessed May 2020]

The Sperm Meets Egg Plan is a step-by-step guide to achieving pregnancy without taking invasive tests, charting temperatures, or making mistakes in predicting your ovulation that result in mistimed attempts at fertilization. From start to finish it takes about 10 to 11 weeks to create a new sperm cell. Both diet and lifestyle can make a difference to sperm quality. The average sperm lives only a few weeks in a man’s body and each ejaculation can set free up to 400 million sperm. This means that men have to make sperm continuously throughout their adult lives. Lodé T. 2020. A brief natural history of the orgasm. All Life 13: 34-44. www.tandfonline.com Opens a new window [Accessed May 2020] During fertilisation, the genetic material in the sperm and egg combine to create a new cell that will rapidly start dividing. This bundle of new cells is known as the blastocyst. It continues travelling down the fallopian tube towards the womb, a journey that can take another three days or so. The placenta is an organ responsible for providing oxygen and nutrients, and removing waste substances. It grows into the wall of the uterus and is joined to the fetus by the umbilical cord. The mother's blood does not mix with the blood of the fetus, but the placenta lets substances pass between the two blood supplies:Deans A. 2018. Your new pregnancy bible. The experts’ guide to pregnancy and early parenthood. 4th edn. London: Hamlyn. Want to work out when you ovulate? Try out our ovulation calculator. Pinpointing the day of ovulation can help you work out your fertile window. Each cycle an egg travels from an ovary through the oviduct to the uterus or womb, where it settles. When the nucleus of a sperm and egg fuse together, the egg is fertilised and it develops into a fetus. Humans typically reproduce by sexual fertilisation and produce offspring that are genetically unique. Fertilisation is the process in which the nucleus of a sperm cell fuses with the nucleus of an egg cell to produce a zygote which will eventually grow into offspring.

You are not actually pregnant until the blastocyst embryo has attached itself to the wall of your womb, where it will develop into a fetus and placenta. Occasionally, the blastocyst will implant somewhere other than the womb (usually in the fallopian tube). This is called an ectopic pregnancy, and it needs urgent medical attention. The pregnancy will not survive outside the womb and needs to be completely treated or removed. The function of the female orgasm is less clear. Theories include that it strengthens the bond between partners, or that uterine contractions help the sperm along their way somehow. We know that a woman doesn’t need to orgasm for conception to happen, though. Uterine contractions happen even without you having an orgasm.NHS. 2018. Trying to get pregnant. Health A to Z. www.nhs.uk Opens a new window [Accessed May 2020] BabyCentre's editorial team is committed to providing the most helpful and trustworthy pregnancy and parenting information in the world. When creating and updating content, we rely on credible sources: respected health organisations, professional groups of doctors and other experts, and published studies in peer-reviewed journals. We believe you should always know the source of the information you're seeing. Learn more about our editorial and medical review policies. Deanna Roy is the six-time USA Today bestselling author of women's fiction. She is a fierce advocate for all the children in her care, biological, fostered, and adopted, and the mothers, who like her, lost babies to miscarriage.