Ultrasounds have long been a thorn in the side of abortion sellers.

This is because the images of hearts beating inside the womb, and of children sucking their thumbs or reacting to outside stimuli, have gone a long way in undercutting the "mass of cells" or "bundle of DNA" theories abortionists pawn to ease the consciences of prospective clients.

And this is why pro-abortion forces demonize the 24 states that require an ultrasound before an abortion -- they know that mothers who look upon their children's faces will have a harder time looking the other way while an abortionist stops a beating heart.

With this understood, abortionists have to be more than a little concerned with the growing number of next-generation ultrasounds, which are taking images and video from inside the womb to unimagined levels.

Four-D ultrasound scans, the latest variants of which were released last year, can be found at hospitals throughout the country and are being used by researchers to watch the development of children in real time.

One group of researchers is currently using 4D to record 24-week-old babies yawning in the womb.

These scans are so advanced that they not only detect and record the yawns, but actually record how long the yawns last and the frequency at which they are occurring.

According to 4D researcher Nadja Reissland, "4D ultra-sound scans are to 3D scans as video footage is to still photos: they are in 3D but also have a time dimension, allowing doctors and researchers to measure how long the behavior they are observing lasts."

As Reissland and other researchers watched the yawns in their testing, they were able to establish habits and patterns that could "serve as an index of health in unborn babies."

If seeing 3D images of babies discouraged mothers from aborting their children, what will 4D videos do?

If seeing the face of her child had a positive impact on the mother, how much more will watching the child yawn and move?

The old storylines of a "mass of cells" or a "bundle of DNA" keep becoming a harder sell for doctors of death.  They, together with some courts and activist groups, may move slowly in admitting that children in the womb are children nonetheless, but ultrasound technology has not proven to be so lethargic.

Steven H. Aden is senior counsel with Alliance Defending Freedom (www.alliancedefendingfreedom.org), a legal alliance employing a unique combination of strategy, training, funding, and litigation to protect and preserve religious liberty and the sanctity of life, marriage, and the family.  Aden heads Alliance Defending Freedom's work to defend the sanctity of life in court from its Washington, D.C., regional service center.