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Sex, Science & Society

Sex, reproduction and impregnation: by 2099 let's not confuse them

Since prehistoric times humans have had sex for reasons other than reproduction

Robert P S Jansen

MJA 1999; 171: 666-667

Introduction - Impregnation's risks and benefits - Reproduction and choice - Sex and vulnerability - References - Authors' details
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Introduction Impregnation -- the entry of sperm into the female body -- is a powerful biological, emotional and social event. Sex is also each of these things. So too is reproduction, or having children. It is important not to confuse the three.


Impregnation's risks and benefits
The human body is no zoological fortress, as the medical fields of virology, bacteriology and parasitology make clear.1,2 Spermatozoa introduced to the reproductive mucosa or elsewhere will sooner or later be phagocytosed by macrophages. Nonetheless, sperm are intrepid: sperm heads can persist in macrophages for seven days or more and, in mice, tritiated-thymidine-labelled DNA from sperm heads in the reproductive tract has been found not just in the uterus, but in the ovaries, the lymph nodes, the spleen, and even the heart.2,3 Through their display of polycationic binding sites, spermatozoa can act as vectors for foreign DNA.4 HIV is concentrated in seminal plasma.1

The chasm that has opened between sex and reproduction needs a paradigm more understanding than abstinence or furtiveness.

Given these risks, why accept impregnation? The one rational reason is for reproduction. Otherwise impregnation appears to be a non-essential side-effect of sex. However, whether fertilisation takes place internally or in vitro, there may be biological benefit to non-conceptional exposure of a woman's immune system to her mate's antigens before reproduction. An increased likelihood of subsequent embryonic survival5,6 and protection against eclampsia7,8 have both been suggested as possible biological benefits of impregnation for a time before conception occurs.


Reproduction and choice
Unless impregnation has been forced,9 a woman nowadays can more or less choose to whose sperm her eggs will be exposed. Ordinarily, she can choose who her mate will be, or she might choose a sperm donor from a commercial sperm bank, such as those that presently flourish in the United States.10 Either way, she is able to make some assessment of the safety of impregnation before attempting to conceive internally.

Reproduction with the use of assisted (ie, non-sex-based or "artificial") insemination is safer if the process is supervised. Australia has strict regulations for medically assisted insemination that compel screening for infectious disease. Because of the possibility of viral contamination it is mandatory to store donated semen for a minimum six months before use, pending repeat testing of the donor. Semen from anonymous donors can already be bought on the Internet; although nominally for purchase by medical practitioners, advertisements are targeted to potential recipients.

The chief hazard with modern, anonymous sperm donation, especially among women not in a heterosexual relationship, and irrespective of the material requirements for raising children, is the lack of a genetic father to identify to the inevitably inquisitive child or children who result.11 Children who have been adopted are winning the right to identify their biological parents in country after country, and it is likely that the same rights will be won by the children of donated sperm, eggs and embryos. Some practitioners in the field of infertility medicine, myself included,11 have chosen to medically facilitate conceptions with donated gametes only when the intending donor is willing to be made known, and preferably to take some part in the child's extended family.

Among sexually reproducing species, the power of choice of mate for the purpose of having offspring of wanted or optimal phenotypic characteristics is probably as ancient as copulation.12 It remains the most potent force for "eugenic" reproduction and is as natural as sex itself, no doubt moving from the subconscious to the conscious in much human reproductive decision making. Yet the vagaries of Mendelian inheritance and homologous recombination mean that a couple's offspring will still manifest wide variation. "Wouldn't it be good if [she/he] had your [this] and my [that]!" we say. And then, as night follows day, we laugh, "But maybe not so good with your that and my this!". At least, within the context of the mate they have chosen, most couples, most of the time, are happy to leave the rolling of the recombining chromosomes to chance.

Conception need not be internal for a woman to reproduce. Developed to overcome infertility caused by destruction of the normal site of conception (the fallopian tubes), by the mid-1980s the certainty conferred by in-vitro fertilisation (IVF) had become proper practice for overcoming many other causes of infertility.13 Through embryo biopsy and molecular DNA testing of an embryonic cell or cells, IVF is also used for the detection of genetic abnormalities before implantation.14

Designer babies? Not quite. Genetic selection for certain traits within a family is not a blank canvas upon which any gene can be placed. To extend the metaphor, the palette cannot for the foreseeable future be broader than the prospective parents' particular genes; assortment is the variable they might try to influence. Charles Darwin had 10 children to express the diversity of his and his chosen mate's genetic phenotypes -- a number considered impractical today by most modern Australian couples. If prospective parents have a strong enough conviction that their child would be better without the burden of a gene or genetic trait that could be stopped, they could choose for implantation only those fertilised eggs that do not bear the unwanted gene.

It is hard to distil valid objections to exercising reproductive choice this way that are distinct from faith-based moral objections to IVF itself15 -- and objectors to IVF on moral grounds have long been in the minority in Australian society.16 Similarly, the use of IVF for sex selection -- a use anticipating genetic testing (with evidence to date in Western countries revealing that there is a slight excess in couples attempting to select a girl as their next baby17) -- comes down to the question of whether reproductive choices in pluralistic societies are to be made by politically compelled governments, by committees of paternalistic strangers, or by the people who will live with the consequences of their decision.

Will IVF widely replace getting-pregnant-by-having-sex? IVF today accounts for more than 1% of all babies born in Australia.18 This number will increase. In real terms, the cost of IVF is falling. Nonetheless, there are reasons why its use will not rise inexorably. The community cannot be expected to subsidise all its personal uses19 and it will continue to be expensive compared with sex and impregnation; it will also continue to be inconvenient and uncomfortable.


Sex and vulnerability
Most animals copulate with the opposite sex only when the female is in oestrus and is susceptible to conception,20 but since prehistoric times humans, like dolphins and bonobo chimpanzees, have had sex for reasons other than reproduction. That this is in principle a natural and expected thing is evidenced by the moral sanction many communities and cultures confer upon sexual intercourse during pregnancy (when another pregnancy can hardly be the goal).

Whatever the particular sexual act might be, morality in a sociobiological context will, it is to be hoped, centre more on the reasons for having sex with the particular other person involved (if there is such a person). When we have sex there is a moral distinction between sex for the expression of love, promotion of fidelity, and mutual sexual relief or fun, on the one side, and the less virtuous motives of domination, emotional entrapment or abuse,9,20 on the other. Sex is inseparable from personal vulnerability and will remain so, and it is in the sharing or exploitation of personal vulnerability that its perennial power for causing good or harm resides.

In my opinion, the social challenge for sex in the new millennium is at once to clarify the separate harms and benefits of impregnation, of reproduction, and of having sex with someone. We need to acknowledge and appreciate the differences, and, when the good outweighs the harm, or when the harm remains imaginary rather than based on evidence, we need to grow comfortable with and to give credence and legitimacy to the unorthodox.

In our modern society we have both an earlier age at puberty and a later age considered suitable for parenthood. Whether it is advice to be comfortable sharing a toothbrush before accepting impregnation, or to regard virginity as lost only when sex has been unprotected from impregnation, the chasm that has opened between sex and reproduction, and into which our blinking adolescents stumble, needs a paradigm more understanding than abstinence or furtiveness.

The singular, responsible satisfaction to be had from mucosal intimacy when sex, impregnation and reproductive intent all come together might or might not be slightly rarer in 2099 than 1999, but it will have lost none of its power to bond a human relationship.

References
  1. Forrest BD. Women, HIV, and mucosal immunity. Lancet 1991; 337: 835-836.
  2. Jansen RPS. Bioethics and the spermatozoon. In: Grudzinskas JG, Yovich JL, editors. Cambridge Reviews in Reproduction. Gametes -- the spermatozoon. Cambridge: Cambridge University Press, 1995: 282-306.
  3. Ball RY, Scott N, Mitchinson MJ. Further observations on spermiophagy by murine peritoneal macrophages in vitro. J Reprod Fertil 1984; 71: 221-226.
  4. Lavitrano M, French D, Zani M, et al. The interaction between exogenous DNA and sperm cells. Mol Reprod Dev 1992; 31: 161-169.
  5. Chaykin S, Watson JG. Reproduction in mice: spermatozoa as factors in the development and implantation of embryos. Gamete Res 1983; 7: 63-73.
  6. Bellinge BS, Copeland CM, Thomas TD, et al. The influence of patient insemination on the implantation rate in an in vitro fertilization and embryo transfer program. Fertil Steril 1986; 46: 252-256.
  7. Duenhoelter JH, Jimenez JM, Baumann G. Pregnancy performance in patients under fifteen years of age. Obstet Gynecol 1975; 46: 49.
  8. Serhal PF, Craft IL. Oocyte donation in 61 patients. Lancet 1989; I: 1185-1187.
  9. Greer G. Raped women in refugee camps. In: The madwoman's underclothes. Essays and occasional writings 1968-85. London: Pan Books, 1987: 108-110.
  10. Jansen R. IVF and reproductive genetics in 1999: biology, business, ethics and sociology. In: Jansen R, Mortimer D, editors. Towards reproductive certainty. Fertility and genetics beyond 1999. London: Parthenon, 1999: 5-7.
  11. Jansen RPS. Reproductive medicine and the social state of childlessness. Med J Aust 1997; 167: 321-323.
  12. Jansen RPS. Bioethics and the oocyte: reproductive choice. In: Grudzinskas JG, Yovich JL, editors. Cambridge reviews in reproduction. Gametes -- the oocyte. Cambridge: Cambridge University Press, 1995: 396-427.
  13. Jansen R. The clinical impact of in-vitro fertilization. Part 1. Results and limitations of conventional reproductive medicine. Med J Aust 1987; 146: 342-353.
  14. Jansen R. Getting pregnant. A compassionate resource for overcoming infertility. Sydney: Allen & Unwin, 1997; 302-308.
  15. Jansen RPS. Evidence-based ethics and the regulation of reproduction. Hum Reprod 1997; 12: 2068-2075.
  16. Brumby M. Australian community attitudes to in-vitro fertilization. Med J Aust 1983; ii: 650-653.
  17. Statham H, Green J, Snowdon C, France-Dawson M. Choice of baby's sex. Lancet 1993; 341: 564-565.
  18. Hurst T, Shafir E, Lancaster P. Assisted conception in Australia and New Zealand 1997. Sydney: AIHW National Perinatal Statistics Unit, 1999; 1.
  19. Jansen R. The clinical impact of in-vitro fertilization. Part 2. Regulation, money and research. Med J Aust 1987; 146: 362-366.
  20. Greer G. Seduction is a four-letter word. Playboy 1973; January: 80-228.


Authors' details
University of Sydney, Sydney, NSW.
Robert P S Jansen, Clinical Professor, Department of Obstetrics and Gynaecology, and Medical Director, Sydney IVF.

Reprints will not be available from the author.
Correspondence: Professor R S Jansen, Sydney IVF, 4 O'Connell Street, Sydney, NSW 2000.

©MJA 1999
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