An unfertilized human egg is a potential human. It is not a person, any more than an acorn is a tree. The moment the egg is fertilized, however, it becomes a microscopic person with a unique genetic code. Similarly, the acorn becomes an oak tree, in seedling stage, when it germinates. Basic science tells us a sprouted acorn is not a lifeless mass; nor is a zygote.

Amendment 48, which stands no chance of passing, would enshrine this fact in the Colorado Constitution. It would establish a rational, scientific, reasonable and legal definition of when human life begins. Voting "yes" on Amendment 48 is a vote for honesty, not a decision to outlaw contraception, abortion, cloning or fetal stem cell research.

Society has decided, for better or worse, that law should not prevent a mother from commissioning the termination of her fetus. The highest court in the land told all 50 states they must protect the rights of mothers to kill fetuses that haven't progressed into the third trimester of pregnancy. But few Americans would support the needless torture of a fetus. Few would support the killing of a preborn child by a drunken driver or an attacker, against the mother's will. Some of America's most pro-choice citizens would object to gratuitous experimentation, abuse or killing of fetuses. A definition of unborn humans as "persons" would aid society in protecting some rights of the unborn, should society choose to do so.

Opponents of the measure have raised alarming concerns. They claim that any woman who takes the morning-after pill, which can abort a fertilized egg, could be convicted of first-degree murder should Amendment 48 pass. They say the law would outlaw abortion, even resulting in criminal investigations each time a woman suffers a natural miscarriage. They don't happen to mention that Colorado is forbidden by federal law to outlaw abortion. They say state law forbids the killing of a "person," so under 48 abortion is doomed. Yet Colorado has the death penalty, and there's no question that death row inmates are "persons."

Abortion is legal in Colorado because state law says it's legal. Colorado law allowed abortion before the United States Supreme Court forbade states to outlaw abortion with its ruling in Roe v. Wade. If the court were to overturn Roe v. Wade, the ruling would merely allow each state to forbid abortion or place limitations on abortion.

In Colorado, with or without Roe v. Wade, abortion would remain lawful during any stage of pregnancy with or without Amendment 48. The fact that Colorado abortion rights exceed the minimum required by Roe v. Wade proves that Roe v. Wade is no factor here. Coloradans so value abortion rights that their laws protect the right of mothers to commission abortions even in the third trimester of pregnancy. Some late-term abortions are purchased because the parents have discovered a fetus has Down syndrome, or a serious physical deformity. Only a "person" gets Down syndrome, so clearly the law allows the killing of persons in some instances.

This is an era in which parents can pay a small fee to get a full-color, high-definition, three-dimensional photo of their thumb-sucking fetus to frame and hang on the wall. So it's hard to believe that Colorado's broadly permissive abortion law reflects a blissful misconception that a fetus is something other than a person. Our abortion law reflects no such misunderstanding, unless the state's average IQ falls somewhere below 50. Instead, our tolerance of abortion reflects a majority mindset that mothers hosting unborn children have rights that far exceed the rights of any fetus at any age. Love it or hate it, that's the law. Amendment 48 would not change it.

Perhaps there was a time of primitive science when intelligent adults didn't know when life begins. It wasn't long ago, after all, that Louis Pasteur faced ridicule and isolation for believing in bacteria - a life form we couldn't see. Those days have passed. The debate regarding legal rights of a fetus should no longer center on the myth that our science is fuzzy. That's a dishonest discussion. Instead, it should focus on what fetal rights a society shall or shall not defend, with full acknowledgement that a fetus is human from the moment of conception.

If abortion laws depend on a misconception that a fetus isn't human, they will not last. If they're based in a societal decision that unborn humans have limited rights, then abortion laws are safe. In their own interest, abortion rights defenders must stop relying on past ignorance and modern mass delusion to support their cause. They must defend their position on a basis of rights; who has them and who does not.

Amendment 48 would merely bring the legal definition of "person" in line with the fact that a fertilized egg is a person in the earliest stage of life. Whether that person has a right to continue living, against his or her mother's will, was long ago decided. The decision has withstood millions of reproductions of in-utero photos and other indisputable evidence that shows us a fetus is a person.

But countless issues regarding fetal rights, affecting mother and child, are likely to arise as science, medicine and technology advance. As society grapples with these issues - such as cloning, organ farming and the parameters of fetal stem cell research - it should do so in a context of human rights, not an indefensible notion that a fetus isn't human.

Amendment 48 would lead to honest discourse, undoing the convenient pretense that we don't know when life begins. We do. A vote for 48 is a vote to get real.