The idea that all embryos begin as female before some transform into males sounds fascinating—but is it scientifically accurate? We asked a top reproductive biology expert to unravel this developmental mystery, and the answer challenges everything many of us thought we knew about our biological beginnings.Taylor Pini has answered Extremely UnlikelyAn expert from University of Sydney in Reproductive BiologyNo, the sex of the embryo is determined at fertilization and depends on whether the sperm that fertilizes the egg carries either an X or a Y chromosome (sperm only carry one or the other because they are "haploid" cells). All eggs carry an X, because females are XX. If the fertilizing sperm carries an X, the resulting embryo will be XX (female) and if the fertilizing sperm carries a Y, the resulting embryo will be male (XY).

We asked three paleontology and evolutionary biology experts if birds are the closest living relatives to dinosaurs. Their answers reveal fascinating connections between creatures separated by 66 million years. From university researchers to paleobiologists, these experts weigh in on whether modern birds are actually living dinosaurs. The evidence might be stronger than you think.Mark N Puttick has answered Near CertainAn expert from University of Bath in Biology, PalaeobiologyToday virtually all scientists support that fact that birds originated from within dinosaurs. The bird-dinosaur link is so widely accepted that dinosaurs of the popular imagination - Tyrannosaurus rex, Brachiosaurus, Triceratops, etc., - are referred to as 'non-avian dinosaurs (e.g., dinosaurs that are not birds). These non-avian dinosaurs went extinct 66 million years ago at the end of the Cretaceous period in a mass extinction most likely caused by a meteorite, but one major group of dinosaurs did not go extinct and still prospers today: the birds.

Despite their dog-like appearance, evolutionary biology and zoology experts reveal a surprising truth about hyenas' family tree. Five specialists weigh in on the taxonomic relationships between these misunderstood carnivores and their mammalian relatives. Their consensus challenges our visual assumptions and demonstrates how evolutionary relationships often defy superficial resemblances. What science tells us about hyena classification might surprise even the most dedicated wildlife enthusiasts.Sarah Benhaiem has answered Near CertainAn expert from Leibniz Institute for Zoo and Widlife Research in Ecology, Ethology, Evolutionary BiologyBatman is correct! Do not trust the appearances: hyenas are more closely related to cats than to dogs, despite their vague resemblance with some canids. The four hyena species (spotted hyena, brown hyena, striped hyena and aardwolf) belong the family Hyaenidae, within the suborder Feliformia (which includes cats), itself within the order Carnivora. Dogs, foxes and wolves also belong to the order Carnivora, but are within the suborder Caniformia.

Check out this answer from Consensus: The average height of males around the world is a complex trait influenced by a combination of genetic, nutritional, and socioeconomic factors. While Northern and Central European countries lead in average male height, regions like tropical Asia and Puerto Rico lag behind due to dietary and socioeconomic challenges. Understanding these variations helps in appreciating the diverse factors that contribute to human physical development.Global Variations in Male HeightEurope and Surrounding RegionsEuropean countries, particularly those in Northern and Central Europe, boast some of the tallest male populations in the world. The Netherlands, for instance, has the highest average male height, reaching approximately 184 cm. This remarkable stature is attributed to high consumption of animal proteins, especially dairy products, and favorable socioeconomic conditions 1.

Yes, dogs can get coronaviruses, but there's no evidence they can spread it to humans. This consensus is based on 3 experts answers from this question: Can dogs get coronavirus?We love our dogs. With ~471million dogs, pet owners worldwide are worried, as it was reported that a Pomeranian in Hong Kong tested positive for SARS-CoV-2. The dog’s owner was positive for the virus and the dog was taken to a nearby animal quarantine facility. We asked Professor John Brownlie, a veterinary pathologist from the Royal Veterinary College in London who studies viruses in dogs. Here are his answers:Can dogs get coronavirus?Yes, they can get coronaviruses. They can become infected with an alpha coronavirus which causes diarrhoea (a vaccine is commercially available) and, in 2003, we discovered a new coronavirus, a beta coronavirus, that we named Canine respiratory Coronavirus (CRCoV). It caused severe respiratory disease in dogs and was rapidly transmitted between dogs in kennels. We have also made a vaccine that is yet to be released. It is similar to both SARS virus and COVID-19 virus but NOT the same virus. There has been no indications, as yet, that this is transmissible to humans, even amongst kennel staff amid the canine infectious respiratory disease (CURD) outbreak. (Full answer here)

Height varies dramatically between individuals. The tallest person ever measured was 2.72m tall, whilst the shortest person stood at just 67cm. We often consider our height as being unchangeable, determined by our genetic makeup from when we were conceived. After all, tall parents usually have tall children and vice versa. Can height be significantly influenced by environmental factors like diet, or is it hard-wired into our DNA? We asked 4 experts in genetics, genomics and cell biology ‘Do environmental factors significantly impact height?’, all 4 said ‘yes’. Here is what we found out. This consensus is based on 6 experts answers from this question: Do environmental factors significantly impact height?What is the evidence that environmental factors impact height?Professor Peter Visscher, an expert in genetics from Queensland University in Australia, says “there is a lot of evidence that height increases over time when countries industrialise and/or get wealthier, and this change must be environmental because genetic factors don’t change over short periods of time (e.g. decades).”He goes on to say that “The likely specific environmental factors are an abundance of food and better healthcare.” Multiple case studies have highlighted how diet affects height. Professor Saverio Alberti, an expert in genetics from Messina University in Italy, says “an example that may fit is the height of newborns during the 1944 famine in the Netherlands.” Children who were born or grew up during this famine were about 4cm shorter than the average Dutch height of the time.