Why does each row of paired spikelets usually produce two rows of corn kernels?

The premise that each row of paired spikelets produces two rows of kernels is a result of the botanical structure of the corn ear. The female inflorescence, which develops into the ear, consists of a thickened axis that bears spikelets in pairs. Because each of these paired spikelets is fertile and capable of developing into a grain, they naturally result in two parallel rows of kernels along the cob.1