Genealogy is the systematic investigation of family relationships, ancestry, descent and kinship across generations. Genealogical research identifies individuals and establishes relationships using evidence such as birth, marriage and death records, census records, wills, probate documents, parish registers, civil registration, property records, military records, immigration documents, inscriptions, newspapers and family papers. Genealogy can concern a single family, a wider lineage or broader questions about population and kinship.
The discipline requires evidence evaluation because names are repeated, records can contain errors and relationships may be described inconsistently across sources. A genealogical conclusion is strongest when independently created records converge on the same relationship. Genealogy is therefore not simply the construction of family trees; it is an evidence based process of identifying people, distinguishing individuals with similar identities and establishing documented relationships.
Genealogical terminology distinguishes several types of relationship and descent. A pedigree generally presents ancestry from a particular individual, while a family group record focuses on parents and children associated with a particular family unit. Lineal relationships connect ancestors and descendants directly, whereas collateral relationships connect people through shared ancestors without direct descent. Patrilineal and matrilineal describe descent traced through male or female lines respectively, while bilateral systems consider ancestry through both sides.
Genealogists must also distinguish biological, legal, social and adoptive relationships because historical records may record different forms of family connection. Terms such as ancestor, descendant, sibling, spouse, parent, child, cousin and affinity describe relationships that require precise interpretation, particularly when historical naming and household practices differ from modern assumptions.
Genealogical evidence varies considerably in reliability and purpose. Civil registration may provide formal information about births, marriages and deaths, but the quality of details depends on the informant and registration system. Census records can identify household composition and approximate ages but may contain spelling differences or inaccurate ages. Parish registers may record baptisms, marriages and burials before civil registration systems existed, although coverage and preservation vary.
Wills and probate records can reveal kinship through named beneficiaries, executors and property arrangements, while land records can connect individuals across generations. Newspapers, directories and electoral records can provide supplementary evidence. A source should not be treated as conclusive merely because it is old or official; its creation date, purpose, informant, jurisdiction and proximity to the event all affect its evidential value.
Identity resolution is one of the central technical problems in Genealogy. Two people may share the same name, while one individual may appear under several spellings or forms of a name. Historical records can contain transcription errors, phonetic spellings, abbreviations, aliases and changes resulting from migration or administrative practices. Age discrepancies are common, and a person's occupation, residence, relatives and witnesses can help distinguish individuals. Genealogists therefore construct timelines and compare multiple records rather than linking people solely by name. Geographic proximity can provide supporting evidence but is not proof of identity. The strongest identification usually combines several independent attributes, such as name, approximate age, occupation, residence, spouse, parents and known children.
Genealogy has a close relationship with demographic history and social history. Family reconstruction can reveal patterns of marriage, fertility, mortality, migration, household formation, occupation and inheritance. Large genealogical datasets can contribute to population studies when their sampling biases are understood. Genealogical evidence can also illuminate historical experiences that are poorly represented in formal political sources, including the lives of women, children, migrants, workers and minority communities. However, surviving records are unevenly distributed. Wealthier families often generated more documents, while poor, mobile or marginalised populations may be poorly documented. Researchers must therefore distinguish the historical population from the portion of that population visible through surviving records.
Genetic genealogy combines DNA analysis with documentary Genealogy to investigate biological relationships and ancestry. Autosomal DNA can identify shared segments with genetic relatives across multiple ancestral lines, while Y chromosome analysis can provide information about direct paternal lines and mitochondrial DNA can provide information about direct maternal lines. Genetic evidence does not replace documentary research because DNA matches require interpretation, shared ancestry can have multiple possible genealogical explanations, and population structure can affect results. Ethical issues include consent, privacy, data sharing and the consequences of discovering unexpected biological relationships. Genetic findings should therefore be integrated cautiously with historical records rather than treated as automatically definitive statements about identity or family history.
Genealogy can be affected by adoption, nonmarital births, remarriage, guardianship, migration, name changes, informal relationships and incomplete records. Historical concepts of family can also differ substantially from modern legal or social categories. A household is not necessarily equivalent to a biological family, and people listed together in a census may have complex relationships.
Common genealogical errors include accepting unsourced online family trees, assuming that people with identical names are the same person, treating family tradition as documentary proof and copying conclusions without checking original records. Digital databases have greatly expanded access to records, but indexes can omit information, misread handwriting or introduce transcription errors. Researchers should inspect original images whenever possible and document the reasoning supporting each relationship.
Genealogy is therefore both a historical research method and a practical way of reconstructing individual and family histories. Important concepts include pedigree, lineage, descent, kinship, collateral relationship, source criticism, identity resolution, proof argument, primary source and secondary source. A rigorous genealogical conclusion explains which records establish a relationship, which evidence is indirect, what contradictions exist and why the proposed identification is preferable to alternatives.
The field has expanded from traditional family history into population research, digital humanities and genetic analysis, while retaining its central requirement that relationships be supported by evidence. Its historical value depends less on producing an attractive family tree than on accurately reconstructing people, relationships and life circumstances from incomplete documentary and biological evidence.
