Is Transposition of the Great Arteries a Consequence of Maternal Hormone Imbalance? Evidence from the Sex Ratios of Relatives of Probands

Transposition of the great arteries occurs more often to males than females: moreover there is reportedly an excess of males among the unaffected relatives of probands. This is construed as evidence that maternal intrauterine hormone levels play a role in the aetiology of this malformation.