From an order which modifies a decree of annulment of marriage to award custody of the minor child of the parties to defendant father, plaintiff mother appeals. She urges that the trial court’s action in changing custody from the mother to the father was an abuse of discretion. Plaintiff’s argument is based upon her view of the sharply conflicting evidence. We have concluded that the order of the trial judge, who saw and heard the witnesses, including the parties, and found upon sufficient evidence that it was for the best interest of the child that custody be awarded to the defendant, cannot be disturbed.
The parties intermarried on November 6, 1941. On March *66131, 1944, the marriage was annulled on the ground that defendant, unknown to plaintiff, had another wife living at the time of his marriage to plaintiff, he apparently having procured an interlocutory, but not a' final, decree of divorce. The decree of annulment awarded custody of the minor child of the parties (a boy then 20 months of age) to plaintiff mother and provided that defendant “may visit with said minor child at all reasonable times and places.” The terms of the order at the time it was made were in accordance with the provisions of an agreement of the parties dated March 15, 1944, and filed with the decree. Such agreement, however, required the plaintiff, within thirty days, to remove from her then place of residence and enter or establish a suitable and proper home for herself and the minor child. Defendant did not appear and was not represented by counsel in the annulment proceedings.
On May 18, 1944, defendant filed his petition to modify the annulment decree to award custody of the child to him. Plaintiff had not changed her place of residence. The modification was sought on the ground that the best interest and welfare of the child would be subserved by it and the petition was based both on the proposition that plaintiff was maintaining the child in an unfit residence and on the proposition that plaintiff was not a fit or proper person to have control of him. After hearing the conflicting evidence the trial judge (the same judge who made the original decree) filed a memorandum opinion in which he found that the home wherein plaintiff and the minor child resided “is orderly, neat, clean, and well-kept,” stated that “The issue in a case such as this is not the condition of the home, but it is the fitness of the parents to supervise the care, custody, and control of the child, and what is for the best interest of the child” (see Prouty v. Prouty (1940), 16 Cal.2d 190, 195 [105 P.2d 295]; Civ. Code, §§ 84, 138, subd. (1)), and found “that the defendant is better fitted to exercise that duty, and it appears that the best interest of the child will be served if he is awarded to the custody of defendant.”
Plaintiff and the minor child lived in the five-room home of plaintiff’s mother. The room which plaintiff and the minor child occupied was small (“six by eight” according to defendant’s testimony) with two small windows, one of which could not be opened. Also residing in the house were plain*662tiff’s mother, her brother and sister-in-law, and the latters’ three-year-old child. Plaintiff received $30 a month from defendant for the support of the child. On about April 10, 1944, she obtained employment at $108 a month. Her sister-in-law cared for the child when plaintiff was at work.
Defendant testified that since the annulment he had seen five black and blue marks across Ms son’s body and that on April 17, 1944, plaintiff’s mother, in the presence of plaintiff, told defendant “about her [plaintiff] being out of humor and probably tired and wore out and she had to pull her off from beating the baby.” Plaintiff testified that she had never whipped the child “to hurt him or make marks” and had never had to be restrained from beating him. Plaintiff’s mother testified that she had never seen the child black and blue from a beating; that “I seen him have marks on him where he tipped a chair on him one day while his father was there. ... I never had to restrain her [plaintiff] from beating [the baby]. I did interfere when I thought she spanked him too hard . . . with her hand.” Introduced in evidence by defendant without objection was a wooden paddle which defendant testified he had seen “used dozens of times” by plaintiff and her sister-in-law to spank the child. Both plaintiff and her sister-in-law testified that they believed in the propriety and effectiveness of such discipline. The paddle was the property of plaintiff’s sister-in-law and was taken by defendant without her permission.
Defendant testified that since the granting of the annulment he had seen his wife under the influence of liquor “several times . . . once or twice a week, on an average.” Defendant had occasion to observe plaintiff come home after work “pretty well intoxicated” because he was at plaintiff's home five or six evenings each week to visit the baby. Plaintiff’s mother and two neighbors testified that they had never seen plaintiff intoxicated. Plaintiff’s sister-in-law testified that she had never seen plaintiff intoxicated in the presence of the minor child. Plaintiff was asked, “Have you been intoxicated in the presence of your minor child?” and answered, “Not that I know of.” She was asked whether she drank “so that you become intoxicated at times,” and answered, “No, it all depends on what you call drunk. If it is passing out, I have never been that way. I have been feeling good.”
Defendant testified that at the time the annulment decree was entered he did not know, but later learned, that plaintiff *663was having “an affair” with a man called Tippie and “If I had known this at the time [the annulment was granted] I would have naturally fought for the baby”; that defendant knew of his own knowledge that Tippie “has had several cases of trouble with other married women. . . . The man worked for us, I known him—my dad and I bailed him out of jail twice. He has a baby of his own and usually every three or four months gets in jail for nonsupport.” On the evening of the 25th of April, 1944, defendant testified, plaintiff told him that Tippie “was over at the house and would like to see me, if I had guts enough to come over . . . with her, he would like to tell me that he had—hadn’t had unchaste relations with her, and so I did.” At 12:45 that night, defendant testified, he saw Tippie crawl through the window into plaintiff’s bedroom where, as stated, the minor child also slept. Plaintiff testified that no man had ever crawled through the window of her room. According to the testimony of plaintiff, her mother and sister-in-law, it would be difficult if not impossible for a man to crawl through this window. In evidence, however, was a letter (which defendant found open in and took from plaintiff’s home) dated May 6, 1944, to Tippie, written but not mailed by plaintiff, reading in part, “If I really thought there was any chance of you coming down, hon, I’d not only have my window made bigger, but I’d even move out in the yard and pitch a tent, then I’d be sure you’d get in.” Plaintiff testified on cross-examination that the reference to the window was “just a gag. . . . He had been kidding about he would come down and crawl in my window.” The letter continues, “Well, daddy darling, here it is 10 o ’clock and I just got home from work. That is, I left at six but Mrs. Eller picked Ina and I up and we stopped in at her place for just one shot and it didn’t end at that. I did feel pretty high for a while, but don’t think I’ll feel so good tomorrow.” Plaintiff testified on cross-examination that she drank four highballs on this occasion.
Plaintiff properly does not contend in her briefs that the above mentioned letter was erroneously admitted in evidence but nevertheless, since the matter has been suggested in discussions in this court, consideration has been given to it. When the letter was offered plaintiff’s counsel objected to it on the ground that it was “incompetent, irrelevant and immaterial. . . . The letter is the property of some person and I think before it can be used in a proceeding of this sort *664it at least ought to he explained how and why he [defendant] came into the possession of it.” (Italics added.) The objection was overruled and on cross-examination defendant explained that while visiting his son he found the letter “laying on the table in the front room in her [plaintiff’s] place, residence . . . laying there unsealed, unmailed” and that he took it and several letters of his own without asking permission of anyone. (After such explanation no motion to strike the letter was interposed.) The letter was properly admitted. The general rule in California is that “where competent evidence is produced on a trial the courts will not stop to inquire or investigate the source from whence it comes or the means by which it was obtained.” (People v. Mayen (1922), 188 Cal. 237, 243 [205 P. 435, 24 A.L.R. 1383]; Herrscher v. State Bar (1935), 4 Cal.2d 399, 412 [49 P.2d 832]; People v. Peak (1944), 66 Cal.App.2d 894, 904-905 [153 P.2d 464].) “The question of the admissibility of evidence wrongfully obtained usually arises in criminal cases. . . . But the use of evidence wrongfully or illegally obtained is not confined to criminal eases and no distinction has ever been made in this respect between civil actions and prosecutions for crime.” (20 Am.Jur. 354, § 393.) The case of Kohn v. Superior Court (1936), 12 Cal.App.2d 459 [55 P.2d 1186], which has been suggested as recognizing a different rule, was a prohibition proceeding arising out of a replevin action and in making its ruling the court carefully pointed out that (p. 463) “the very issue before the court was whether the documents in suit had been wrongfully taken from this plaintiff.” The ruling and discussion in that case have no pertinence to any question in the case at bar. Even if, as to the admissibility of such evidence, a distinction between purely private right actions and those in which a public interest is involved were proper, the public interest rule should prevail here. This is not a mere adversary proceeding between plaintiff and defendant. On the contrary the controlling rights are those of the minor child and of the state in the child’s welfare, and the trial court properly so held.
It has also been suggested that certain opinion evidence, given by witnesses who were acquainted with defendant, to the effect that he was a good father and a fit and proper person to have the custody of his son, was “entitled to no consideration.” Regardless of the weight to which such testimony was entitled no prejudicial error in its receipt is shown. Both plaintiff and defendant, severally (without *665objection, from the other except in one instance), adduced such evidence from various witnesses in support of their respective claims to fitness. The testimonies of the witnesses who stated opinions largely concerned observation by the witnesses of the conduct and character manifestations of the parties and to that extent was certainly not improper. As to one question addressed to one witness for defendant, which question called for the witness’ opinion as to defendant’s fitness to “raise his son,” plaintiff objected on the ground that the question was “incompetent, irrelevant and immaterial and no proper foundation has been laid.” So far as foundation for the question is concerned the witness had testified that she had known the defendant for fourteen years and that he roomed in the home of her husband and herself. Even if we assume that the opinion asked for was incompetent there was no prejudicial error as three other witnesses were permitted to give testimony to the same effect without objection. Furthermore, it may be noted that plaintiff’s mother, who was a witness for plaintiff, on cross-examination testified that defendant was “greatly concerned about the welfare of his child”; that “I guess he is a good father, all right, as far as feeding and loving and things like that go.”
Defendant testified that he roomed and boarded with Mr. and Mrs. Granberg (Mrs. Granberg is the witness above mentioned who was permitted over objection to give her opinion as to defendant’s fitness to raise his son), who have two daughters, aged about 11 and 15; that if he was awarded custody of his son he intended to take him into the Granberg home; that “Mrs. Granberg is very willing to be a mother to him, when I am not there.” Mrs. Granberg testified to the same effect.
The evidence as to defendant’s conduct, like that above summarized as to the conduct of plaintiff, is sharply conflicting. Except for the admitted taking of the letter and paddle which defendant introduced in evidence, the testimony as to conduct of defendant which, plaintiff asserts, indicates his unfitness to have custody of the minor child, relates to occasions prior to the annulment. Even if all testimony as to defendant’s past misconduct was believed, nevertheless “The question as to whether a parent is a fit or proper person to have the custody of a minor child refers ... to his or her fitness at the time of the hearing and is not necessarily controlled by conduct . . . prior thereto. [Citations.] ” *666(Prouty v. Prouty (1940), supra, 16 Cal.2d 190, 194 [105 P.2d 295].)
Plaintiff relies on the proposition that, as between parents adversely claiming custody, “other things being equal, if the child is of tender years, it should be given to the mother.” (Civ. Code, § 138, which refers to actions for divorce; the proposition is equally applicable here.) The evidence above recited is clearly sufficient to support the determination of the trial court that “other things” are not equal in this ease. “In determining whether other things are equal within the meaning of the above code section, the trial court is necessarily allowed a wide latitude in the exercise of its discretion. In the first instance it is for the trial court to determine, after considering all the evidence, how the best interests of the child will be subserved. The question is to be determined solely from the standpoint of the child, and the feelings and desires of the contesting parties are not to be considered, except in so far as they affect the best interests of the child.” (Taber v. Taber (1930), 209 Cal. 755, 756 [290 P. 36].) It is settled that “An application for a modification of an award of custody is addressed to the sound legal discretion of the trial court, and its discretion will not be disturbed on appeal unless the record presents a clear case of an abuse of that discretion. [Citations.] ” (Foster v. Foster (1937), 8 Cal.2d 719, 730 [68 P.2d 719].)
This court has recognized (Foster v. Foster, supra, at pp. 726, 728 of 8 Cal.2d) that generally “until some change of circumstances arises which makes a modification of the former order of custody advisable from the point of view of the welfare of the child, the court will give effect to the former order and will refuse to make any modification of such order, ’ ’ but that there may be cases “in which, despite the fact that there was apparently no change of circumstances, nevertheless, the welfare of the child might require that the previous order of custody be changed” (citing Bogardus v. Bogardus (1929), 102 Cal.App. 503, 506 [283 P. 127]), or “in which some fact, secret and hidden at the time of the entry of the former judgment, would in the interest of the welfare of the child, justify a court in modifying the former order of custody despite the fact that there had been no actual change of circumstances since the entry of the former order” (citing Olson v. Olson (1928), 95 Cal.App. 594, 597 [272 P. 1113]; Titcomb v. Superior Court (1934), 220 Cal. 34, 39 [29 P.2d 206]). The above epitomized evidence is clearly suffi*667cient to support findings both that circumstances had changed and that facts material to the welfare of the child were “secret and hidden” from defendant at the time the original decree was entered. Under such circumstances there is no tenable basis for a court of appellate function to hold that the trial court abused its discretion in ordering the change of custody.
The trial court ordered “That the full care, custody and control of the minor child ... be and he is hereby awarded to defendant.” Defendant now suggests that the order be modified to permit “the mother to visit the child at all reasonable times and places, provided that she is not- under the influence of intoxicating liquor.” The question of plaintiff’s right of visitation was not mentioned at the hearing and plaintiff has confined her argument to urging that the order be reversed. Defendant’s suggested modification of this present award of custody is therefore a matter not within the province of this court on the record before us.
For the reasons above stated the order appealed from is affirmed.
Gibson, C. J., Shenk, J., Edmonds, J., Traynor, J., and Spence, J., concurred.