333
votes
Russian Dolls - How do they reproduce?
Through selective breeding and misplaced import laws, we only ever get to see Russian dolls that are "aesthetically pleasing".
In the wild, it is relatively common to get a "double-yolker" - that is, ...
- 3,375
135
votes
Russian Dolls - How do they reproduce?
In the deepest, darkest, hidden places in the forest dwell the Queen Dolls.
Rarely seen, these creatures resemble a normal Russian Doll only at the tops of their vast, misshapen bodies - their lower ...
- 1,552
100
votes
Russian Dolls - How do they reproduce?
Actually, there is an organism on earth that is vaguely similar to the Russian dolls that you describe. The volvox:
Individual volvox cells, a kind of freshwater algae, reproduce in the conventional ...
- 1,127
85
votes
Accepted
What could a reptilian race tell by candling their eggs?
Developing comments between @AlexP and me into an answer...
As other answers have said, candling of reptilian eggs is possible. For in ovo testing of chicken sex, if the male and female have ...
- 21.3k
78
votes
Accepted
Is pregnancy in zero-g a barrier to long term space living?
Last time I looked into this I was amazed these experiments (mammalian conception to delivery in orbit) had not been done. I figured I just had not found it and so I dug in this time. For mammals, ...
- 306k
76
votes
How poor does Elven fertility need to be in order to keep the ratio of humans to elves constant?
The different causes of death are the biggest issue here.
Humans will lose a lot of children to disease, elves don't seem to suffer from this
Humans lose fertility early then die fairly young, again ...
- 118k
69
votes
Designing an animal that wants to be eaten
That's not too hard. There are plenty of real-life animals that want to be eaten. They're either parasites, or the hosts of parasites, whose behavior is modified by the parasite that they carry.
Of ...
- 42.7k
63
votes
Accepted
Why would sperm cells derived from women's stem cells always produce female children?
Biology for dummies:
Because of how sex determination works for humans, women carry XX chromosomes, men carry XY chromosomes.
No matter how hard you try, from a woman's cell you won't get a Y ...
- 301k
62
votes
Accepted
How could a female member of a species produce eggs unto death?
The concept of a menopause is actually unusual, it's known to exist in the wild in 5 species, Humans, Orcas, Belugas, Narwhals, Short Finned Pilot Whales. While some other species exhibit menopause ...
- 118k
62
votes
How would a planet-size entity reproduce?
If the creatures can be mistaken for planets, then by duck typing, they must have the following properties:
They orbit stars,
They have sufficient mass to assume hydrostatic equilibrium (a nearly ...
- 142k
58
votes
Plausible cause of a family only giving birth to females?
Its been observed that jet-pilots tend to have more girls than boys. Its even something of an inside joke among aviation types. Its been given some scientific credence lately when it was theorised ...
- 21.2k
56
votes
Accepted
Should immortal women have periods?
You can go through with a normal cycle, menstrual cycle runs as normal, menopause runs as normal at a certain age, after which no more periods. You can say that the immortality means that the normal ...
- 118k
56
votes
Elf-like race: What could prevent overpopulation?
Low natality rates.
They would live long, but procreating a child is a very rare event for all couples.
That should balance the lack of aging, if deaths due to other reasons are not too frequent.
- 301k
53
votes
How could an abortion cause infertility in a witch?
To get pregnant again, you must finish your prior pregnancy.
The woman cannot have another pregnancy because she has never finished the prior one. It is not because she has been physically damaged ...
- 306k
48
votes
How would a planet-size entity reproduce?
A different take on Daron's answer:
They play god--guided evolution. All that junk in our DNA? Some of it is actually the genetic material of the planet-beings. The sentient star travelers are the ...
- 31.2k
47
votes
If angels and devils are the same species, why would their mortal offspring appear physically different?
Here are two creatures of the same species:
If you and most of your kin looked like the first picture, you would probably consider the second picture--10 times larger, with an un-naturally slim face, ...
- 85.8k
46
votes
What would make human males an inefficient option for spreading alien genes?
The aliens have no game. Human women somehow have the uncanny ability to detect their desperation to mate. Protecting the purity of the human race, one rejection at a time.
- 11.1k
44
votes
Is there a paternity test method given medieval level technology with low false positive rate?
In the Middle Ages they had not one but two absolutely certain paternity tests.
If the mother was married, then the husband of the mother was the father of the child, according to the legal maxim ...
- 98k
42
votes
Russian Dolls - How do they reproduce?
Regenerate the top part.
The splitting doesn't actually kills the doll - just its bottom half.
The bottom half becomes a nest for the little doll that was gestating on the inside of the "mother doll"...
- 9,115
37
votes
Plausible cause of a family only giving birth to females?
Self produced testosterone antibodies.
As soon as the male embryo starts producing testosterone, it gets attacked by the mother's antibodies and as a result cannot complete its development.
- 301k
37
votes
Russian Dolls - How do they reproduce?
Budding and out-growing.
Budding: each outer doll, once in a while, produces a bud, which in this case is a tiny Russian doll. Once it detaches from the mother body, it starts living on its own.
Out-...
- 301k
36
votes
Is there a paternity test method given medieval level technology with low false positive rate?
Given medieval technology there is no reliable paternity test. It wasn't until the 1960s when genetic testing to determine paternity became possible. HLA testing had a 80% success rate and couldn't ...
- 21.4k
35
votes
What effect would a means of reproduction without pregnancy have on the population?
You haven't nailed down the process, which is rather important as to how it will affect the population. Let's consider this solely from the perspective of the magic tree and blood...
This process ...
- 132k
33
votes
How would interspecies lovers with alien body plans safely engage in physical intimacy?
With clear communication and active consent.
I'm going to assume discussion and light contact (eg hugs) just works between species. It sounds like your asking more about the sexual side of intimacy ...
- 44.4k
32
votes
Accepted
Elf-like race: What could prevent overpopulation?
Aging is not necessary to maintain their low population. No population can grow without limit, and in the animal kingdom, most animals die before they would otherwise die of extreme old age.
These ...
- 41.6k
32
votes
Why would a 'first world' alien opt to have a brood of dumb children rather than one smart one?
It is tough to be pregnant. Get it over with!
It is not easy to be pregnant. It is physically taxing and draining. Sentient females given the option may choose not to become pregnant at all. ...
- 306k
32
votes
Accepted
How do the eggs of birds that fly using their legs not crack?
The uterus does not participate in the mechanical stresses of movement.
It is not invited to that party and it does not want to go. A uterus has uterus things to worry about. It no more participates ...
- 306k
31
votes
Should immortal women have periods?
Well, human women have all their eggs pre-made -- they are born with a finite number of eggs and that's what they will ever have. If you want immortal women to have an infinite number of periods you ...
- 98k
31
votes
How would a planet-size entity reproduce?
Hitch a ride on Spaceships.
Renan mentioneed these creatures cannot possibly make physical contact and live to tell the tale. The answer suggests spores, meaning much smaller particles that get shot ...
- 66.3k
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