BOSTON — Case study one: a pregnant woman wants an abortion. Her husband doesn't. Should he have a say?
Case study two: a woman wants to become pregnant with frozen embryos. Her ex-husband opposes the decision. Should he have a say?
The answer, legally, is no in the abortion case, and in the case of frozen embryos, almost always yes.
It might seem paradoxical, but it is emblematic of the way technology is changing the landscape of human reproduction. And it is the kind of paradox that could get more attention with the nomination of Judge Samuel A. Alito Jr. to the Supreme Court.
Since his nomination, Judge Alito's most talked-about decision so far has been his dissent in the 1991 Pennsylvania abortion case, Planned Parenthood v. Casey.
In that case, Judge Alito wanted to uphold a Pennsylvania law that required women to notify their husbands when seeking an abortion. His view was rejected by the majority of the judges, and later, by the Supreme Court, which used the case as a vehicle to uphold the legality of abortion.
The Casey decision effectively left the decision of whether to have an abortion entirely up to the woman. But in cases involving frozen embryos, judges have given equal weight to the father's point of view.
"It's fascinating because they are sort of developing on dual tracks without a whole lot of reference back and forth," said David D. Meyer, a University of Illinois law professor, about the divergent outcomes in cases involving abortion and frozen embryos.
With abortion, said Marsha Garrison, a professor at Brooklyn Law School, the courts recognize that "that embryo is in the woman's body, it's within her and can't be separated from her, so it's not just her decision-making about whether to bear a child, it's about her body."
Ms. Garrison said even if a man is tricked into impregnating a woman, many courts have held that "well, it just doesn't matter: if you engage in sexual intercourse, you assume the risk that a child will be born."
With embryos, however, everything changes, said June Carbone, a law professor at the University of Santa Clara. "There's nothing that involves her physical integrity," she said, "and there is a notion that this would be a violation of the parenthood of the father" not to take his wishes into account.
The watershed case was a 1992 decision by the Tennessee Supreme Court, which ruled that a man could prevent his ex-wife from using or donating embryos that they had created during their marriage in an attempt to have children.
IN that case, the couple had not signed a contract specifying what should be done with the leftover embryos. But some courts, including one in Massachusetts in 2000, have said that even if both parties signed a contract giving the woman the right to the embryos in case of divorce, such a contract could not be enforced. "Either parent cannot be forced to become a parent in circumstances where they object, even if they signed a contract," Professor Carbone said.
The dichotomy in the courts' treatment of abortion and embryos could change the approach of fathers' rights advocates. For years, they have argued that there is a basic unfairness in the lack of a father's input in an abortion decision. "A mother can terminate a pregnancy and the father has no say," said Michael McCormick, executive director of the American Coalition for Fathers and Children. "On the other hand, a mother's able to make a unilateral decision to keep the child and saddle the father with 18 years of child support."
But what if fathers' rights groups used the embryo issue to gain more leverage? Jeffery M. Leving, a Chicago lawyer and fathers' rights advocate, has created a print advertisement aimed at fathers in embryo cases: "Dads, protect the fate of your potential unborn children," it says.
Mr. Leving, who opposes abortion in most cases, last year led an unsuccessful attempt to get Illinois to pass a law requiring women seeking abortion to notify their husbands. "I believe that if we get newsworthy frozen embryo cases, it could bring media attention to the rights of fathers in the abortion area," he said.
While most fathers' rights groups have a right-to-life cast to them, antiabortion groups and fathers' rights advocates might find they eventually part company. In embryo cases, courts have almost always ruled that in the case of a dispute, the embryo cannot be implanted and no child will be born.
Of course, ultimately, technology could change things yet again. Fathers may end up with rights in abortion cases, Professor Garrison said, "if the day ever comes when men can become pregnant or we have artificial incubators" so that a woman's womb is unnecessary.