“Babies who are this small, he says, have a good chance of survival. Small is not good for babies. It is not whimsical or cute or the cause of admiration. It is the first time it occurs to us that they might not survive. Babies die from smallness.”

Claire Lynch knew that having children with her wife would be complicated but she could never have anticipated the extent to which her life would be redrawn by the process.

This dazzling debut begins with the smallest of life’s substances, the microscopic cells subdividing in a petri dish in a fertility treatment centre. She moves through her story in incremental yet ever growing steps, from the fingernail-sized pregnancy test result screen which bears two affirmative lines to the premature arrival of her children who have to wear scale-model oxygen masks in their life-saving incubators. Devastatingly poignant and profoundly observant – and funny against the odds – Claire considers whether it is our smallness that makes our lives so big.