I’m curious if people have the same reaction of disbelief to an analogous situation: Punnett squares where two heterozygous parents have kids, but being homozygous recessive is fatal very early in pregnancy. What fraction of the resulting offspring in that case will be homozygous dominant? In that case, the fact that an offspring survives at all tells us they are not homozygous recessive, which in the gender example is analogous to ruling out two girls. But the 1:2:1 pattern in biology is extremely robust and was known all the way back to Mendel—green and yellow peas are still how we teach genetics in high school.
I’m curious if people have the same reaction of disbelief to an analogous situation: Punnett squares where two heterozygous parents have kids, but being homozygous recessive is fatal very early in pregnancy. What fraction of the resulting offspring in that case will be homozygous dominant? In that case, the fact that an offspring survives at all tells us they are not homozygous recessive, which in the gender example is analogous to ruling out two girls. But the 1:2:1 pattern in biology is extremely robust and was known all the way back to Mendel—green and yellow peas are still how we teach genetics in high school.