More than a hundred couples gathered in parks and conference rooms this week to meet a man offering something that is illegal in Australia: choice of their baby’s sex.

Australian guidelines ban pre-implantation genetic tests for sex selection based on concerns around gender bias, social imbalance and the psychological effect on these children.

In the US, however, it is increasingly marketed for “family balancing”.

This week, Californian-based fertility specialist Dr Daniel Potter conducted a rapid-fire tour across Sydney, Melbourne and Brisbane, hosting seminars with prospective customers.