This is just an interest check to see if people are interested in this basic idea.
The characters are all members of a large support group for couples that went to a fertility clinic to try to have children only to discover that one of them has a medical problem. Dozens of couples unable to have children because either the husband or the wife are actually sterile.
One of the women though had recently become pregnant, but to her close friends she'll admit that the father of her unborn child isn't her husband - she was raped by a man in a fox mask while her husband was away on a business trip. But the fact that the rapist knew that her husband was out, that she was fertile, that she wanted a baby so badly that she's keep one raped into her - it's hard to come up with any other conclusion.
One (or possibly more) of the fertile husbands in the group have targeted the fertile women to rape them and to give them the children themselves. There's a Fox in the Hen House.