Then there's the Craig Thomson affair, which is also in the news. That saga relates to his alleged use of union funds to procure services from prostitutes.
This kind of thing keeps happening the world over. It seems that at any given time there's at least one government being threatened by problems caused by the sex life of one or more of its members.
Clearly, sex and political power are inextricably linked. There's that great line from Henry Kissinger: "Power is the ultimate aphrodisiac." He meant that it was an aphrodisiac for women. But it seems to make men a lot more libidinous as well.
In the case of Julia Gillard the problem seems almost inverted. Her past sexual relations indirectly threaten her present authority.
In any case, that link is a two edge sword: Sex is always causing problems for the powerful!