U.S. State Department officials and family planning groups such as Planned Parenthood said they expect Obama to overturn the "Mexico City" policy, first instituted by the Reagan administration.

CNN: Obama may reverse Bush policies on stem cells, drilling, abortion

On questions such as gay marriage, abortion and funding for Planned Parenthood, a family-planning group, Mr Romney, his running-mate Paul Ryan and his party have big electoral weaknesses among women, especially younger ones.

ECONOMIST: The campaign

David Kesterton, parenthood and community project manager at the Family Planning Association, says there are a variety of sensible and practical reasons why men are having children later in life.

BBC: Older fathers: what's behind the trend?

Yet it is hard to believe that the Republicans' problem with women has not been aggravated by Mr Santorum's obsession with who is doing what to whom in the bedroom, or by Mr Romney's promise to defund Planned Parenthood, the organisation on which millions of poor women depend for family planning (including abortion), or by the antics of Republican state legislatures.

ECONOMIST: Lexington