What do zebras, doe, deer and goats have in common? Everyone, it turns out, is able to determine for themselves what the sex of their offspring will be. Already 30 years ago, the American biologist Robert Trivers discovered that the red deer has this ability, but not all scientists accepted the results of his research. Some claimed that the phenomenon exists only in species where there are few strong males, who control courtship and mating with the females. In such cases, the skeptics argued, the males would prefer that a male be born.
Now scientists from the University of Edinburgh and Oxford in the UK are discovering that Trivers was right, and that there are other mammals with a similar ability. Their research, reported in the journal American Naturalist, revealed that the same is true for zebras, doe and goats.
The possibility of choosing the sex of the offspring depends on the environmental conditions: the males are brought into the world when conditions are especially favorable for their growth, while the females are brought into the world when the conditions are less favorable. Although these characteristics are already known for bees and wasps, the current study presents the "first conclusive evidence" of this ability in vegetarian ungulates.
In humans, this requires external intervention - manipulation in IVF treatments. The entire procedure is still ethically controversial. The current opinion in Israel regarding the issue is that spouses can determine the sex of the newborn if there is a medical genetic reason for it.
