The Argument begins with a sex scene. Unathletic, feral sex scene, scored by unferal, unsexy jazz piano music, wherein Susan Rome and James Whalen claw at one another’s clothes while contemplating, if only with their animal brains, the carnal possibilities of living room and kitchen furniture. She, the 42-year-old painter Sophie, has followed Him, the 49-year-old trader Phillip, home to his swank, high-ceilinged Manhattan crib after a party.

As on basic cable, they wake from their night of passion with their underwear still on. Neither of them do this sort of thing, naturally. Their bashful morning-after negotiations over cereal have an authenticity that make us hope things will work out for them. Whoever was responsible for the projections in Phillip’s windows, whether it was scenic designer Robbie Hayes or lighting designer Martha Mountain or someone else, does an admirable job simulating predawn light. It’s good that director Shirley Serotsky attends to this sensuous detail of their otherworldly evening. She’ll be conjuring up the red-eyed nausea of lovers’ all-night battles soon enough.

Neither the playwright, Alexandra Gersten-Vassilaros, nor Theater J considers this a secret, so: Sophie gets pregnant. And then she must make a Sophie’s, uh, decision. Which Phillip considers to be partially, and in his weaker moments, entirely, his.

There you go: To Not Be, or Not to Not Be?

Gersten-Vassilaros has done her job in making real the anguish of two normally reasonable people who disagree, sincerely and extremely, on how to handle an unexpected pregnancy. (In a program note, she says she’s updated the work since its 2005 debut, though nothing about it feels especially timely.) “Children turn lovers into relatives,” Sophie tells Phillip. As with Kathleen Turner and Michael Douglas in The War of the Roses, a not-wholly-believable exchange of escalating hostilities will turn their lust into bloodlust. Rome and Whalen, though? Completely believable.

The ending Gersten-Vassilaros settles on feels like a bid to make sure the audience hangs around for the post-show discussion, whether there’s one scheduled or not. Her aim, she says, is to ping-pong our sympathies from Sophie to Philip throughout. I can’t say my sense of whom I agreed with wavered for a second. But I’ll confess I had been dreading sitting through “the abortion play” only to find it richly drawn and fully absorbing. Oh, the humanity.