Helen Lathrop executed a will in 1972, which placed her estate in a trust, with the income to be distributed to her siblings, or, if a sibling died, to that sibling’s living issue. Upon the death of the last sibling the trust was to be distributed to her siblings’ then-living children. Lathrop died in 1972 and her estate was distributed to Wells Fargo Bank (the bank) as trustee. Lathrop’s brother, Earl Mitchell, died in 1993. Mitchell had a biological son, Jon Newman, who was adopted out of the family in 1946. The bank (plaintiff) petitioned the court for a determination as to whether Newman was the “issue of” Mitchell at the time of Mitchell’s death.