“Penhall's gruesomely entertaining new comedy … Penhall is onto an absolute winner here, taking an inspired idea and using its inversion of normal biological procedure to breed a fertile mix of existential questions and corporeal, sometimes gross-out humour ... there’s nothing out there that cuts with anything like this double-edged finesse to the heart of how we manage the whole birth business in this country and to the core of vexed issues about who does what in modern relationships.” – Dominic Cavendish, Telegraph
“Penhall allows us to put the pieces together as we please. Ninety minutes of entertainment or deceptive think-piece, it’s still a healthy, bouncing bundle.” – Ian Shuttleworth, Financial Times
“This often hilarious and provocative play is wonderfully fertile, so to speak ... It’s a tribute to Penhall that you sit there wondering why no one has thought of putting it centre stage … Birthday is full of joys” – Paul Taylor, Independent