Test tube in liquid nitrogen representing cryopreservation of reproductive samples, commonly collected and maintained by sperm banks
Non-coital reproduction in humans, sometimes referred to as sexless human reproduction[note 1] or external human fertilization, is the occurrence of human reproduction in which fertilization of an oocyte by a spermatozoon (gamete fusion) occurs without sexual intercourse or without skin-to-skin physical contact between the genetic parents. The term covers clinical and non-clinical techniques that bring gametes together either inside the reproductive tract (e.g., intrauterine insemination) or in vitro (e.g., in vitro fertilization), and therefore falls within the scope of assisted reproductive technology rather than any form of asexual reproduction.[1]
Non-coital reproduction, in general, refers to the fusion of gametes and the resulting offspring which doesn't involve physical touch, referring to non-intimate procreation by both humans and certain animal species alike.
Overview and terminology
In discussions of human reproduction, it is important to differentiate between sexual activity and the biological fusion of gametes. Sexual activity, or sex, generally refers to physical interaction between two individuals’ bodies, including penetration, oral sex, mutual masturbation, and other sexual acts. While the traditional definition of sexual intercourse focused narrowly on penis-in-vagina penetration, sociological and feminist literature notes that this definition has broadened over time to encompass a variety of sexual behaviors that do not result in pregnancy or reproduction.[2]
In contrast, fertilization occurs when a sperm cell successfully merges with an egg cell, regardless of whether physical sexual contact has taken place. Non-coital reproduction, such as assisted reproductive technologies (ART), exemplifies this distinction: sperm and egg may meet in vitro or through clinical procedures without any sexual activity between the parents. Misunderstandings sometimes arise when the presence of gamete fusion is conflated with sexual activity, leading to debates over terminology such as "asexual reproduction" in humans, which is etymologically inaccurate but occasionally employed descriptively.
Clarifying this distinction is particularly important in medical, social, and ethical contexts. It separates biological parenthood from sexual behavior, showing that humans can reproduce without engaging in sexual acts. At the same time, it recognizes that modern definitions of sexual intercourse in humans are broader than mere procreation, encompassing behaviors that may carry social, relational, or emotional significance without producing offspring.[3]
Non-coital reproduction encompasses procedures and practices by which sperm and egg meet without intercourse between partners. These practices may be clinical (performed in regulated fertility clinics) or non-clinical (performed at home), and include intra-vaginal or intrauterine placement of sperm, laboratory fertilization of eggs followed by embryo transfer, and the use of surgically retrieved gametes. Although these methods can remove the requirement for physical sexual contact between partners, they do not remove the requirement for gametes; fertilization remains a sexual, meiotic process at the cellular level.[4][5][6]
Popular or metaphorical use of the term "asexual" to describe non-coital or technologically assisted human conception is explicitly distinct from the biological definition of asexual reproduction and should be regarded as a non-technical usage rather than a scientific classification.
Hypothetical non-coital fertilization in early humans
It is theoretically possible that conception could occur if viable sperm were introduced into the female reproductive tract without sexual intercourse. In a purely hypothetical scenario, early humans could have deposited semen outside the body, which another individual then introduced into the vagina. Although biologically conceivable, such hypothetical non-coital fertilization would face numerous practical obstacles. Sperm exposed to air or foreign surfaces rapidly lose motility, and environmental factors such as temperature, drying, and contamination further reduce viability. Even under ideal conditions, conception in this manner would be far less reliable than natural intercourse. Anthropologists note that while early humans may have had extensive knowledge of reproductive cycles and fertility, no ethnographic or archaeological record indicates intentional use of semen outside the body for procreation. Modern assisted reproduction demonstrates that intentional sperm introduction can succeed, but these methods rely on controlled laboratory or clinical environments.
There is currently no anthropological or archaeological evidence that such non-coital methods were ever practiced by hunter-gatherers or other pre-modern human populations.
Types of assisted reproduction
Assisted reproductive technology (ART) encompasses a range of medical and non-medical techniques used to achieve pregnancy without sexual intercourse. These methods vary in complexity, invasiveness, and clinical oversight, but all involve the use of gametes to effect fertilization. ART procedures are commonly employed to address infertility, avoid genetic disease transmission, or enable reproduction for individuals or couples who cannot conceive through intercourse alone.[1]
Artificial insemination
Artificial insemination involves the placement of sperm into the female reproductive tract by means other than sexual intercourse. Variants include:
Intravaginal insemination (IVI), in which semen is placed into the vagina, often performed outside of clinical settings. This method relies on natural sperm migration through the cervix and is generally considered less invasive but also less effective than clinical insemination techniques.
Intrauterine insemination (IUI), a clinical procedure in which processed sperm is placed directly into the uterus, usually timed to ovulation to increase the probability of fertilization. IUI bypasses the cervical barrier and is frequently combined with ovulation-inducing medications to improve success rates.[7][8]
In vitro fertilization (IVF)
In vitro fertilisation involves the retrieval of oocytes from the ovaries, fertilization with sperm in a laboratory setting, and subsequent transfer of one or more embryos into the uterus. IVF bypasses several natural barriers to fertilization and is commonly used in cases of tubal factor infertility, advanced maternal age, or unexplained infertility. The procedure allows for direct observation of fertilization and early embryonic development and may involve the cryopreservation of surplus embryos for future use.[9]
Intracytoplasmic sperm injection (ICSI)
Intracytoplasmic sperm injection is a specialized form of IVF in which a single spermatozoon is injected directly into an oocyte using micromanipulation techniques. ICSI is frequently used in cases of severe male factor infertility, low sperm count, or impaired sperm motility. This method enables fertilization even when sperm are unable to penetrate the egg naturally and is commonly employed following surgical sperm retrieval.[5][10]
Use of donor gametes
Assisted reproduction may involve the use of donor sperm, donor eggs, or donated embryos. Donor gametes are screened according to medical and regulatory standards that vary by jurisdiction and may be used in both insemination and IVF procedures. The use of donor material may be indicated due to genetic concerns, absence of viable gametes, or social circumstances, and often involves legal frameworks governing consent, anonymity, and parental rights.[11]
Sperm retrieval techniques
In cases where sperm cannot be obtained through ejaculation, sperm may be surgically retrieved directly from the reproductive tract. Techniques include:
Percutaneous epididymal sperm aspiration (PESA)
Testicular sperm aspiration (TESA)
Testicular sperm extraction (TESE)
Retrieved sperm may be used immediately or cryopreserved for later use in IVF or ICSI cycles. These techniques are commonly applied in cases of obstructive azoospermia, prior vasectomy, or other conditions preventing sperm from entering the ejaculate.[12]
Sperm banking and cryopreservation
Sperm banking involves the collection and cryopreservation of semen for future reproductive use. Cryopreserved sperm may be stored for extended periods without significant loss of viability and later used in artificial insemination or IVF procedures. Sperm banking is commonly utilized prior to medical treatments that may impair fertility (such as chemotherapy), before vasectomy, or for donor sperm programs. Long-term storage protocols allow sperm to remain viable for many years under appropriate cryogenic conditions.[1][9][13]
Intracytoplasmic sperm injection (ICSI)
Intracytoplasmic sperm injection (ICSI) is a micromanipulation technique often used when sperm quality or number is low; a single sperm is injected directly into an oocyte to effect fertilization.[9][5]
Sperm retrieval and cryopreservation
Men who cannot provide ejaculate sperm (for example, post-vasectomy or with obstructive azoospermia) may have sperm retrieved directly from the epididymis or testis (e.g., PESA, TESA, TESE). Retrieved sperm may be used fresh or cryopreserved (banked) for later intrauterine insemination or IVF/ICSI cycles.[12][14]
Motivations for non‑coital reproduction
Individuals and couples pursue non‑coital reproduction for a variety of personal, social, medical, and practical reasons. One common motivation is the desire to have a biological child in the absence of a male partner. Single women increasingly seek fertility treatments such as sperm donation and in vitro fertilisation (IVF) to start families without intercourse, with single patients rising from 1,400 to 4,800 IVF or donor insemination cycles in the UK over a decade.[15]
Same‑sex female couples also commonly use reciprocal IVF or donor sperm so one partner can provide eggs while the other carries the pregnancy, enabling shared biological parenting.[16]
Medical infertility is another key driver: individuals and couples may use sperm donation or donor gametes when male partners produce insufficient or no viable sperm, or when genetic risks exist. Some women opt for artificial insemination when conditions such as endometriosis or severe oligozoospermia make sexual conception unlikely.[17]
Social definitions of infertility now often include “social infertility”, where relationship status or sexual orientation, rather than medical inability, drives a need for assisted methods.[18]
Individuals may also pre‑emptively freeze gametes to preserve future fertility when delaying parenthood for career or personal reasons.[19]
Men may donate sperm for altruistic reasons or to help friends or family build a family, though donor shortages remain common in many countries.[20]
Using assisted methods rather than manual insemination can reduce risks of contamination, ensure correct timing relative to ovulation, and provide access to high-quality sperm or eggs from donors when needed. Couples may also prefer ART to maintain privacy, minimize emotional or physical discomfort, or to take advantage of pre-implantation genetic testing and other reproductive technologies.[21][22]
These motivations reflect a diversity of reproductive goals, encompassing family structure, personal identity, medical necessity, and social circumstance, all of which can lead individuals to pursue conception without intercourse.
Spectrum of procreation
Human and animal procreation can be categorized into three primary modes, highlighting whether physical sexual activity is required and the biological mechanism involved:
Asexual reproduction
* Gametes are not involved. * Offspring are genetically identical to the parent. * Examples: parthenogenesis in some invertebrates and vertebrates.[23]
Non-coital gamete reproduction
* Gametes (sperm and egg) are required. * Fertilization occurs without physical sexual contact. * Human examples: assisted reproductive technologies (ART) such as IVF, ICSI, and donor insemination.[24] * Animal examples: external fertilization in corals, sea urchins, and amphibians.[25]
Copulation (sexual intercourse)
* Gametes are required. * Fertilization occurs via physical sexual activity. * Includes penis-to-vagina intercourse, or other sexual acts that result in gamete transfer. * Offspring are genetically unique, arising from combined parental gametes.[26]
In many animal species, fertilization can occur without direct physical copulation between adults. This typically takes the form of external fertilization, where males and females release their gametes into the environment and the sperm and eggs unite outside the bodies of the parents. External fertilization is particularly common among aquatic organisms, such as many bony fish and amphibians, where eggs and sperm are synchronised in time and space to increase the likelihood of fertilization as water currents bring gametes together.[27]
Broadcast spawning, a form of external fertilization in which large numbers of gametes are released simultaneously, occurs among corals and echinoderms such as sea urchins; eggs and sperm mix in the water column and fertilization ensues without any physical mating behaviour.[28][29][30] Similarly, many fish species release eggs and sperm during spawning events triggered by environmental cues, relying on the surrounding water to facilitate gamete contact and fusion.
Many species of toads reproduce via external fertilization, where females deposit eggs in water and males release sperm over them. Fertilization occurs outside the bodies of the adults, often during synchronized breeding events, eliminating the need for physical copulation while still requiring gamete fusion.[31]
Legal, ethical and social considerations
Non-coital reproduction raises legal, regulatory and ethical issues that vary by jurisdiction, including donor screening, recordkeeping, parentage and consent, distribution of medical risks, and access to services. Many countries regulate clinic-based ART and advise caution regarding home insemination with donor sperm because of infectious-disease screening, legal parentage, and counselling considerations.[11][32]
Asexual identity and assisted reproduction
Some individuals who identify as asexual (“ace”) report having little or no sexual attraction or low sexual desire. Many asexual individuals describe little or no interest in sexual activity but may still desire romantic or emotional relationships, and may choose different paths to family building that do not involve intercourse.[33]
↑Zegers‑Hochschild, F; Adamson, GD; Dyer, S (2017). "The International Glossary on Infertility and Fertility Care, 2017". Fertility and Sterility. 108 (3): 393–406. doi:10.1016/j.fertnstert.2017.06.029. PMID28865547.
↑Templeton, AA; Wagstaff, R; Edwards, RG (1986). "Factors affecting the outcome of in‑trauterine insemination: a prospective study". British Journal of Obstetrics and Gynaecology. 93 (10): 102–107. doi:10.1111/j.1471-0528.1986.tb07853.x. PMID3801350.
↑Palermo, G; Joris, H; Sermon, K (1992). "Pregnancies after intracytoplasmic injection of single spermatozoon into an oocyte". Nature. 357 (6380): 207–209. doi:10.1038/357207a0.
↑Schulz, SM; Hermann, BP (2019). "Sperm cryopreservation and reproductive outcomes: a review". Reproduction. 158 (3): R97 –R112. doi:10.1530/REP-19-0168 (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Kumari, V; Dhaliwal, GK (2015). "Effect of advanced paternal age on semen quality and reproductive outcome". Journal of Human Reproductive Sciences. 8 (2): 70–74. doi:10.4103/0974-1208.165158 (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Bay, J (2024). "A systematic review of reproductive technologies for shared conception in same-sex female couples". Human Reproduction. doi:10.1093/humrep/dey123 (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Smith, A (2023). "Understanding the Reasons Why Men and Women Do Not Donate Gametes". Reproductive Sciences. 30 (5): 1651–1659. doi:10.1007/s43032-022-01112-9.
↑Hammarberg, K (2013). "Couples' decision-making regarding assisted reproductive technologies". Human Reproduction. 28 (11): 2985–2994. doi:10.1093/humrep/det321. PMID23904466.
↑Simmonds, MC (2000). "Asexual reproduction in vertebrates: parthenogenesis and its occurrence". Journal of Zoology. 252: 1–15. doi:10.1111/j.1469-7998.2000.tb00767.x (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Levitan, DR (1998). "The ecology and evolution of fertilization in broadcast-spawning invertebrates". Ecology. 79: 2020–2034. doi:10.1890/0012-9658(1998)079[2020:TEAEOF]2.0.CO;2 (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Campbell, NA (2021). Biology, 12th Edition. Pearson. pp.645–650.
↑"Coral Spawning". Flower Garden Banks National Marine Sanctuary / NOAA. Retrieved 27 December 2025.
↑Szmant, AM; Giese, AC (2009). "Modes of reproductive ecology in broadcast spawning corals". Journal of Marine Biology. 2009: ID 748178. doi:10.1155/2009/748178 (inactive 27 December 2025).{{cite journal}}: CS1 maint: DOI inactive as of December 2025 (link)
↑Duellman, WM; Trueb, L (1994). Biology of Amphibians. Johns Hopkins University Press. pp.90–95.
↑Ethics Committee of the American Society for Reproductive Medicine (2019). "Electronic address: asrm@asrm.org; Deferred ethical issues in assisted reproductive technology". Fertility and Sterility. 111 (4): 681–689. doi:10.1016/j.fertnstert.2019.02.019. PMID30982605.
↑Scherrer, K (2008). "Coming to an Asexual Identity: Negotiating Identity, Negotiating Desire". Sexualities. 11 (5): 621–641. doi:10.1177/1363460708094269. PMID20593009.
Further reading
World Health Organization. Infertility: a public health perspective. WHO publications and fact sheets on infertility and ART.
American Society for Reproductive Medicine (ASRM) patient information on ART and ICSI.
↑Due to descriptive language, it is often referred to as asexual reproduction or non-sexual production, despite such terms being etymologically inaccurate.
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