Bio-Tech: Sexual and Reproductive Modifications

Adjusting human fertility and sexual potency or pleasure has been an obsession of humanity since prehistoric times. The tools of magic, folk remedies, surgery, and drugs may soon be joined by genetic engineering.

Genetic modification of the testes and ovaries may alter the way children are conceived and the development of sexual characteristics. Some possible modifications are described below. Most are 0-point features, but they will often have a dramatic effect on a person’s life or the way that society functions.

Sex Ratios

Most animals we are familiar with produce equal numbers of males and females. A common method in fiction of emphasizing that a species is alien is to alter this ratio. Some thought about why real creatures have an equal sex ratio can lead to interesting conclusions about fantasy or science fiction species that don't.

It may seem evolutionarily wasteful to produce as many males as females. After all, one male can fertilize dozens of females – as is the case in harem-keeping species such as sea lions – so why use valuable food resources to produce superfluous males? The answer comes from the interplay of biology and mathematics. Let's assume:

1. A species has two sexes.
2. An individual inherits an equal number of genes from each parent.
3. Those genes form the basis of evolution.

The evolutionary success of a group of genes is measured by one thing only: how many offspring those genes produce. If a population consists of more females than males, then – on average – each female produces fewer children than each male (since the number of children divided by the number of females is less than the same number of children divided by the number of males). So for genes to produce more offspring, it is better for them to be in a male body. Over time, evolutionary pressure will produce more males. The opposite applies if there are more males; either way evolution tends to even out the sex ratio.

For natural species in a hard science setting, assumption 3 is a given. Changing assumption 1 can lead to interesting aliens, but a similar argument proves that a species with any number of sexes must produce each sex in equal numbers.

Some familiar species on Earth don't have equal sex ratios: ants and bees. They manage this by breaking assumption 2. Male ants and bees do not have fathers – they get all their genes from their mother. The breeding members of ant and bee colonies are produced in a 3-1 female-male ratio. This also raises the question of sterile worker castes – most ants and bees are actually sterile. Since such drones don't reproduce, they don't enter the above arguments, and can be produced in any numbers.

So naturally evolved species usually either have equal sex ratios, an unusual genetic inheritance mechanism, or sterile castes. But if they were gengineered recently (or exist in a fantasy or superscience setting), then all bets are off.

Altered Sex Ratio

This modifies the average ratio of male to female births. This can be a specific ratio (e.g., five women to every man) or even eliminate births of either sex. These changes may be made to correct a perceived imbalance, or for deliberate attempts at social engineering. However, although an altered sex ratio can be programmed by gengineer fiat, it will naturally drift back to equal ratios over evolutionary time, assuming the species is allowed to evolve (see box). 0 points.

Cross-Species Surrogacy

See Cross-Species Surrogacy Exotic Perk.

Easy Childbirth

Modifications to the structure of the pelvis to help mothers deal with the delivery of (large-headed) human babies have been an ongoing part of human evolution; further ergonomic improvements may be possible via genetic engineering. The ability to shut down many (but not all) pain receptors during delivery may also be welcomed by many women. This advantage gives a +2 to HT rolls to determine the success of any pregnancy. 0 points.

External Development

Early development in the fetus focuses on the respiratory and gastrointestinal systems. It can be born radically premature; this reduces gestation time (see Shorter Gestation) to as little as half-normal. After birth it requires immediate transfer of the fetus to an incubator unit or a marsupial pouch (see Payload under Other Transgenic Traits) to complete development. 0 points.

Light Menses

Alterations to female ovulation and hormone function could ensure post-pubescent women experience greatly reduced monthly discomfort due to PMS and menstruation, as well as the later problems of menopause. This may result in either a very mild period or, if taken in conjunction with Reproductive Control, no menstruation at all. 0 points.

Estrus

This is another approach to avoiding menstruation, altering humans to become fertile for perhaps one month of the year (much like cats or dogs). This is normally worth 0 points, since the advantages and disadvantages cancel out. Males can also have a version of this. Variant humans (male or female) with this feature often have Lecherousness (12; Accessibility, Only in mating season, -80%) [-3] but it is not mandatory.

Reproductive Control

This allows females to control their fertility. This will usually require a day or so to adjust hormonal levels. Combined with the Light Menses modification, this means a woman has a period only if she voluntarily chooses fertility in a particular month. Alternatively, and for the same point cost, a female could be able to absorb an early fetus back into the womb, like a rabbit, with pregnancy being canceled on a successful Will roll. 1 point.

Sexual Orientation

Some credible theories suggest a tendency toward heterosexuality, bisexuality, homosexuality, pansexuality (and many others) may be partially or even largely predetermined by genetic inheritance. If so, gengineers should be able to select sexual preference before birth, a procedure with potentially explosive social consequences. This could also include an orientation toward partners of another species. 0 points.

Shorter Gestation

Shorter conception-to-birth periods than the human average of 266 days may be possible by modifying human growth factors or altering the chemical environment in the womb. This is convenient for the mother, as well as allowing faster population growth – but careful gengineering will be needed to ensure that the fetus develops normally. A reduction to two-thirds the normal gestation period is possible; for alternatives, see Oviparous or External Development. 0 points.

Extended Fertility

As lifespans increase, genetic engineering may be used to extend the period in which both sexes can produce children. With this feature, fertility is retained until latter in life. 0 points.

Increased Fecundity

This modification means that a woman is more likely to experience multiple births; releasing two eggs every ovulation, for example, could result in twins in as many as one-quarter of all pregnancies. It is a good idea to combine this 0-point feature with the Easy Childbirth feature. 0 points.

Hermaphroditism

Individuals with both male and female primary and/or secondary sexual characteristics occur naturally in some humans, but usually the mutation is vestigial, and not noticed until puberty. Genetic engineering would allow the reliable creation of functional hermaphrodites. A "utopian" society might try to give everyone this trait to ensure sexual equality (no sexual discrimination if everyone is both sexes). 0 points.

Hermaphromorphs

At TL10+, genetic enhancement might create functional "hermaphromorphs" able to switch sexes or be both at once, which a tolerant culture might find interesting. These often have the limitation "cannot change if pregnant" (-20%).

Oviparous

The fetus is born contained in a soft-shelled egg. This requires a larger birth weight, as food for the infant needs to be contained in the egg with it, but requires a less developed fetus. The gestation time may be cut down to as little as 1/3 normal (see Shorter Gestation, above). The egg must be kept warm until hatching (which takes the remainder of the normal gestation period), through constant care or in an incubator.

Parthenogenesis

In females, this may be possible through very high-tech gengineering of the human ovum and reproductive organs. A woman's egg cells would carry a complete chromosome map, and could be diverted to her womb, then brought to term. Pregnancy would be triggered by voluntary hormonal changes learned through biofeedback, or by taking a pill ($1-10). The fetus would effectively be her clone. Parthenogenesis is a superior strategy for rapidly increasing a race's numbers, and might be deemed viable for an all-female sub-race. It means the race won't change, but if they have the capability to gengineer themselves, then natural evolution is probably no longer something to worry about. Parthenogenesis is a 0-point feature if the race only reproduces through parthenogenesis, or a Perk if it can also use sexual reproduction. 0/1 points.

Exotic Genitalia

This may include "improved" shape or texture, extra organs in the same or new places, or sensitive erectile tissue added to other areas, such as lips or finger tips. Such modifications may be limited to specialized pleasure models in some societies; in others, they may be standard equipment for everyone. If the modification is designed to simply enhance or modify the user's own experience, this is a 0-point feature. If it enhances his ability as a lover, this will grant a racial bonus to Erotic Art skill.

Modified Genetic Inheritance

This alters the operation of the sex chromosomes so males and females inherit different fractions of their genes from each parent. This could result in schemes such as those used by ants and bees (see Sex Ratios), or might be used to produce genetically viable individuals with normally rare sex chromosome mutations. This could be done to produce a parahuman species with an altered sex ratio that will survive long-term evolution, but has little effect in the short term. 0 points.

Variant Sexual Schemes

This could give humanity additional sexes, including sterile "drones." Schemes involving three or more reproductive sexes will require other biological changes (and social adjustments!), but a drone sex would be relatively easy and potentially useful (and would be Neutered or Sexless). 0 or -1 point.

Sexual and Reproductive Modifications Table

Trait	Cost	TL
Altered Sex Ratio	0	9*
Cross-Species Surrogacy	1	10*
Easy Childbirth	0	10*
Estrus	0	9*
Exotic Genitalia	0†	9*
Extended Fertility	0	9
External Development	0	10*
Extreme Sexual Dimorphism	1†	9
Hermaphromorph	5	10*
Increased Fecundity	0	9
Light Menses	0	9
Modified Genetic Inheritance	0	10*
Neutered or Sexless	-1	10
Oviparous	0	10*
Parthenogenesis	0 or 1	10*
Reproductive Control	1	9*
Sexual Orientation	0	9
Sterile	0	9
Shorter Gestation	1	10*
Variant Sexual Schemes	0	10*

* Species modification.

† May justify a racial skill modifier giving +1 to +3 to Erotic Art at a cost of 2 points per +1 skill.