As with "Mitochondrial Eve", the title of "Y-chromosomal Adam" is not permanently fixed to a single individual, but can advance over the course of human history as paternal lineages become extinct.

For example, in 2013, the discovery of a previously unknown Y-chromosomal haplogroup was announced,[4] which resulted in a slight adjustment of the estimated age of the human Y-MRCA.

As of 2015, estimates of the age of the Y-MRCA range around 200,000 to 300,000 years ago, roughly consistent with the emergence of anatomically modern humans.

[6] The same holds for the concepts of matrilineal and patrilineal MRCAs: it follows from the definition of Y-MRCA that he had at least two sons who both have unbroken lineages that have survived to the present day.

Age estimates based on this published during 2014–2015 range between 160,000 and 300,000 years, compatible with the time of emergence and early dispersal of Homo sapiens.

These features of the Y chromosome have slowed down the identification of its polymorphisms; as a consequence, they have reduced the accuracy of Y-chromosome mutation rate estimates.

[10] Methods of estimating the age of the Y-MRCA for a population of human males whose Y-chromosomes have been sequenced are based on applying the theories of molecular evolution to the Y chromosome.

Y chromosomes within a specific haplogroup are assumed to share a common patrilineal ancestor who was the first to carry the defining mutation.

)[citation needed] A family tree of Y chromosomes can be constructed, with the mutations serving as branching points along lineages.

[12] This date also meant that Y-chromosomal Adam lived at a time very close to, and possibly after, the migration from Africa which is believed to have taken place 50,000–80,000 years ago.

One explanation given for this discrepancy in the time depths of patrilineal vs. matrilineal lineages was that females have a better chance of reproducing than males due to the practice of polygyny.

[15] In 2013, Francalacci et al. reported the sequencing of male-specific single-nucleotide Y-chromosome polymorphisms (MSY-SNPs) from 1204 Sardinian males, which indicated an estimate of 180,000 to 200,000 years for the common origin of all humans through paternal lineage.

[16][17] Also in 2013, Poznik et al. reported the Y-MRCA to have lived between 120,000 and 156,000 years ago, based on genome sequencing of 69 men from 9 different populations.

[18] As these ranges overlap for a time-range of 28,000 years (148 to 120 kya), the results of this study have been cast in terms of the possibility that "Genetic Adam and Eve may have walked on Earth at the same time" in the popular press.

[7][19] The announcement by Mendez et al.[4] of the discovery of a previously unknown lineage, haplogroup A00, in 2013, resulted in another shift in the estimate for the age of Y-chromosomal Adam.

[2] The same study reports that non-African populations converge to a cluster of Y-MRCAs in a window close to 50 kya (out-of-Africa migration), and an additional bottleneck for non-African populations at about 10 kya, interpreted as reflecting cultural changes increasing the variance in male reproductive success (i.e. increased social stratification) in the Neolithic.

The rearrangement of the Y-chromosome family tree implies that lineages classified as Haplogroup A do not necessarily form a monophyletic clade.