(dissenting).
I would reverse the decision of the trial court. As this court said in Stearns v. Stearns, 80 S.D. 443, 446, 126 N.W.2d 124, 126:
When children of tender years are involved our law favors the mother, SDC 14.0505 [now SDCL 30-27-19], and her statutory preferential right cannot be denied or defeated in the absence of some compelling reason such as an indication that her custody of the children would be detrimental to their best interest and welfare.
As recently as September of 1977, we held that the exercise of a trial court’s discretion in awarding custody of children of tender years must have a sound and substantial basis in the testimony. Kester v. Kester, S.D., 257 N.W.2d 731. I find no such basis here. True, appellant may have demonstrated that she was an unfit wife by virtue of her conduct with another man, but it does not necessarily follow from that that she is not a fit and proper person to have custody of her children. Wiesner v. Wiesner, 80 S.D. 114, 119 N.W.2d 920. It is true that during the unsettled period following her separation from respondent, appellant did move about to different places under less than desirable living conditions and with resulting impermanence in the chil-drens’ school 'attendance. Given her past performance as a more than adequate parent, however, I do not believe that this temporary period of personal instability in living style and duration of residence was so destined to continue that it constituted a compelling circumstance warranting the award of custody to respondent. However unworthy her personal conduct may have been during the time in question, there is nothing in the record to support a finding that it had a detrimental effect on the children.
The effect of the trial court’s decision is to award custody of two young children to an over-the-road truck driver who by the very nature of his work must of necessity frequently be away from his home. For all practical purposes, the children will be reared by their sixty-four year old grandmother, who, although without question a highly educated woman of broad professional experience, finds herself in the position of being required to fill a role that only a person of younger years is by nature designed to fill. To say that her care, concern, and love cannot substitute for that of the children’s mother is to do her no dis*645credit; it is only to recognize that which a wide disparity in ages must reveal.
Implicit in what has been said above is my conclusion that these children are of tender years. Although there may very well be cases in which the evidence would support a finding that children of somewhat older years had advanced beyond the age of tender years, as far as I can tell the record before us contains no such evidence. That being the case, how can it be said that it was for the trial court to determine whether these two children were or were not of tender years?
I would reverse the judgment and decree and remand the case with instructions to enter an order awarding custody of the children to appellant.