County of El Dorado v. Misura

• Decision Date: 15 March 1995
• Docket Number: No. C017199,C017199
• Court: California Court of Appeals Court of Appeals
• Parties: , 63 USLW 2656 COUNTY OF EL DORADO, Plaintiff and Appellant, v. Bill MISURA, Defendant and Respondent.

Page 908

38 Cal.Rptr.2d 908

33 Cal.App.4th 73, 63 USLW 2656

COUNTY OF EL DORADO, Plaintiff and Appellant, v. Bill MISURA, Defendant and Respondent.

No. C017199.

Court of Appeal, Third District, California.

March 15, 1995.

As Modified on Denial of Rehearing April 11, 1995.

Review Denied July 13, 1995.

Daniel E. Lungren, Atty. Gen., Roderick E. Walston, Chief Asst. Atty. Gen., Carol Ann White, Supervising Deputy Atty. Gen., and Mary Jane Hamilton, Deputy Atty. Gen., for plaintiff and appellant.

Howard M. Hoffman, Sacramento, for defendant and respondent.

NICHOLSON, Associate Justice.

A woman has intercourse with several different men and conceives a child. Years later, she identifies one man as the father and blood tests show this man closely matches the genetic characteristics expected of the child's father. By statute, these test results trigger a presumption of paternity. (Fam.Code, § 7555, former Evid.Code, § 895.5.) The other men are not tested. We conclude evidence of the mere existence of other, untested, men is insufficient of itself to rebut the statutory presumption of paternity based on genetic testing.

The Attorney General prosecutes this appeal from an adverse ruling dismissing a paternity complaint. We construe the premature notice of appeal from this nonappealable ruling to encompass the judgment.

                (9 Witkin, Cal.Procedure (3d ed. 1985) Appeal, § 414, pp. 411-413.)   We need address but one of the arguments:  whether substantial evidence supports the trial court's decision.  On this question we disagree with the reasoning and analysis proffered by the Attorney General, but we agree no substantial evidence supports the judgment.  We reverse with directions
                

FACTS

The specifics of the testimony will be revisited later, after a discussion of the scientific significance of it. However, to provide context we offer the following precis:

The child was born on October 17, 1982. The mother had sex with defendant around the time of the Pig Bowl, which was played on January 23, 1982, about nine months before. (See fn. 3, infra.) The trial court's opinion is muddled on this point, but the statement of facts in defendant's respondent's brief states without qualification that the mother had intercourse with him during the period of conception. Defendant is bound by this concession. (Mangini v. Aerojet-General Corp. (1991) 230 Cal.App.3d 1125, 1152, 281 Cal.Rptr. 827; Federer v. County of Sacramento (1983) 141 Cal.App.3d 184, 186, 190 Cal.Rptr. 187; 9 Witkin, op. cit. supra, § 482, pp. 472-473.) There was evidence that during that period the mother may have had sex with three other men. Based on certain blood tests, when comparing defendant to a random man there was a 99.69% relative chance he was the father, even assuming the mother had three other sex partners. Defendant's "paternity index" was 970, more than enough to trigger a statutory presumption of paternity.

DISCUSSION

I Genetic Testing of Blood

Some knowledge of the science underlying genetic testing is necessary to understand the legal issue raised in this case. "In a paternity trial, a fact-finder is naturally tempted to seize upon statistical figures, like the paternity index or the probability of paternity, as lifelines of objective truth in a sea of prevarication. 'Soft' evidence involving difficult questions of credibility and other circumstantial matters may be submerged or lost because it appears unnecessary to resolve the questions in light of the hard, scientific, mathematical proof. Under these circumstances it is absolutely essential that the significance of the mathematical proof be clearly understood by both counsel and the fact-finder." (Peterson, A Few Things You Should Know About Paternity Tests (But Were Afraid to Ask) (1982) 22 Santa Clara L.Rev. 667, 684, fn. omitted.)

Through testing of blood and tissue, particularly HLA (human leukocyte [white blood cell] antigen) testing, certain genes can be identified. If a child has a gene not contributed by the mother, it was contributed by the father. If a man could not have contributed the gene, he is not the father. But the converse is not true; merely because he could have contributed the gene does not prove the man is the father. Thus, genetic testing alone cannot establish paternity. By itself, at most it can only preclude paternity. (See Comment, DNA Fingerprinting and Paternity Testing (1989) 22 U.C.Davis L.Rev. 609, 614.)

Certain genes are more or less common in given human populations. If the putative father possesses uncommon genes which must have been contributed by the child's father, often it is said there is a greater likelihood or probability he is the true father, expressed as a high paternity index or "probability of paternity." (DNA Fingerprinting and Paternity Testing, supra, 22 U.C.Davis L.Rev. at pp. 616-617.) But the assumption misleads. (Peterson, supra, 22 Santa Clara L.Rev. at pp. 669, 685.) This "likelihood" exists only because we assume the man had what is obliquely referred to as "access to the mother." (E.g., In re Paternity of M.J.B. (1988) 144 Wis.2d 638, 425 N.W.2d 404, 409.) Regardless of the genetic makeup of the putative father, if he is infertile or did not have access to the mother, he is not the father. Without access there can be no paternity. (Id. 425 N.W.2d at p. 410.) The trier of fact cannot find a defendant is the father based solely on expert testimony. Such testimony must be coupled with so-called "nongenetic" testimony ("soft" evidence) establishing access.

A joint committee of the American Bar Association and American Medical Association promulgated certain guidelines which, in combination with standards set by the American Association of Blood Banks (AABB), create the backdrop for expert testimony in a particular case. (Joint AMA-ABA Guidelines: Present Status of Serologic Testing in Problems of Disputed Parentage (1976) 10 Fam.L.Q. 247 (hereafter Guidelines ); see generally Walker, Inclusion Probabilities in Parentage Testing (1983).) A brief explanation of certain terms follows.

The probability of exclusion (or "prior probability of exclusion") is "the probability that the tests employed will exclude a falsely accused man. If the probability of exclusion with the tests employed is 95%, of 100 non-fathers 95 will be excluded and 5 will not be excluded.... This does not mean that there is a 95% chance that the alleged father is the true father.... [T]here is no direct relationship between the probability of exclusion and the likelihood of paternity. Likelihood of paternity cannot be extrapolated from the probability of exclusion.... The significance of the probability of exclusion is that if he is not excluded as a possible father, the likelihood of paternity can be estimated by considering other available empirical evidence." (Division of Family Services v. Guffey (Mo.App.1990) 795 S.W.2d 546, 548, fn. 2, italics omitted.) Confusingly, a separate "probability of exclusion" is specific for the given mother-child combination. (Peterson, supra, 22 Santa Clara L.Rev. at p. 679; see Reisner and Bolk, A Layman's Guide to the Use of Blood Group Analysis in Paternity Testing (1981-1982) 20 J.Fam.L. 657, 671 (hereafter A Layman's Guide ).)

The paternity index, sometimes called the "likelihood ratio," or "chance (or likelihood) of paternity," "involves the probability that a cross between the [putative father] and the mother would produce an offspring with the child's phenotypes and the corresponding probability for a random selection of genes from the male population." (Kaye, Plemel as a Primer on Proving Paternity (1988) 24 Willamette L.Rev. 867, 877 (hereafter Proving Paternity ).) "Despite the alternative labels, it is not the probability that the accused is the father." (Plemel v. Walter (1987) 303 Or. 262, 735 P.2d 1209, 1213, italics in original; see Guffey, supra, 795 S.W.2d at p. 549, fn. 2.) The chance of paternity is the paternity index converted into a percentage. ¹ (Plemel, supra, 735 P.2d at p. 1214.)

The probability of paternity (or "posterior probability of paternity") is the probability the putative father is the true father of the child in question, and is a term often misused and misunderstood. The probability of paternity must take into account the "soft" or "nongenetic" evidence in the case. Such "soft" evidence is converted into a figure known as the "prior chance" or "prior probability of paternity." For example, if but one man had access to the mother, his prior probability of paternity (the probability of paternity without considering the genetic evidence) would be 100%. His posterior probability of paternity (the probability after considering the genetic evidence) would also be 100%, because the "soft" evidence establishes paternity, regardless of the genetic evidence. If a man had no access to the mother, his prior probability of paternity would be zero as would his posterior probability of paternity. Again, regardless of the genetic evidence, the nongenetic evidence establishes nonpaternity. (Plemel, supra, 735 P.2d at p. 1215.)

But the nongenetic evidence is never this simple. In most cases the trier of fact has some evidence of access and some evidence of nonaccess. "Since these absolutes cannot be known, we can estimate these values as 90% for a strong pro-paternity case and 10% for a weak case. Traditionally, laboratories use a neutral figure of 50% in their calculations. When 50% is used, the likelihood of paternity is mathematically identical to the probability of paternity. Hence when laboratories ignore the prior probability they are assuming it is 50%, a figure which may or may not be appropriate." (A Layman's Guide, supra, 20 J.Fam.L. at p. 674; see Proving Paternity, supra, 24 Willamette L.Rev. at pp. 878-881.)

Use of the 50% figure means it is as likely the putative father had access to the mother as the random man. Some courts view this assumption of equal access as an...