Sydney's Catholic Archbishop has questioned whether the gender imbalance caused by the selective abortion of female foetuses could hinder the rise to affluence of China and India.

Cardinal George Pell yesterday addressed the annual scientific meeting of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists on the topic of whether religious faith was compatible with women's health around the world.

Cardinal Pell used his address to highlight the abortion of female foetuses by couples in China and India that wanted sons.

He quoted statistics showing that there were 32 million more boys than girls under the age of 20 in China and 7.1 million fewer girls than boys up to the age of six in India. ''The social consequences of these infamous policies over the next few decades are likely to bring new meaning to the term of reaping the whirlwind,'' Cardinal Pell said.

''As well as coping with the unpredictable consequences of tens of millions of single men - they can't all become Catholic priests - this must raise serious questions about whether we're entering the Chinese century.''

Cardinal Pell said abortion represented a tragic and collective failure to provide care and support to women.