Darwin married twice and had 14 children, including two illegitimate daughters by an employee, and, possibly, at least one further illegitimate daughter.

In 1757 he married Mary (Polly) Howard (1740–1770).
They had four sons and one daughter, two of whom (a son and a daughter) died in infancy:
Charles Darwin (1758–1778), uncle of the naturalist
Erasmus Darwin II (1759–1799)
Elizabeth Darwin (1763, survived 4 months)
Robert Waring Darwin (1766–1848), father of the naturalist Charles Darwin
William Alvey Darwin (1767, survived 19 days)
The first Mrs. Darwin died in 1770.
A governess, Mary Parker, was hired to look after Robert.
By late 1771, employer and employee had become intimately involved and together they had two illegitimate daughters:
Susanna Parker (1772–1856)
Mary Parker Jr (1774–1859)
Susanna and Mary Jr later established a boarding school for girls.
In 1782, Mary Sr (the governess) married Joseph Day (1745–1811), a Birmingham merchant, and moved away.

Darwin may have fathered another child, this time with a married woman.
A Lucy Swift gave birth in 1771 to a baby, also named Lucy, who was christened a daughter of her mother and William Swift, but there is reason to believe the father was really Darwin.
Lucy Jr. married John Hardcastle in Derby in 1792 and their daughter, Mary, married Francis Boott, the physician.

In 1775 Darwin met Elizabeth Pole, daughter of Charles Colyear, 2nd Earl of Portmore, and wife of Colonel Edward Pole (1718–1780); but as she was married, Darwin could only make his feelings known for her through poetry.
When Edward Pole died, Darwin married Elizabeth and moved to her home, Radbourne Hall, four miles (6 km) west of Derby.
The hall and village are these days known as Radbourne.
In 1782, they moved to Full Street, Derby.
They had four sons, one of whom died in infancy, and three daughters:
Edward Darwin (1782–1829)
Frances Ann Violetta Darwin (1783–1874), married Samuel Tertius Galton, was the mother of Francis Galton
Emma Georgina Elizabeth Darwin (1784–1818)
Sir Francis Sacheverel Darwin (1786–1859)
John Darwin (1787–1818)
Henry Darwin (1789–1790), died in infancy.

Harriet Darwin (1790–1825), married Admiral Thomas James Maling
Darwin's personal appearance is described in unflattering detail in his Biographical Memoirs, printed by the Monthly Magazine in 1802.
Darwin, the description reads, "was of middle stature, in person gross and corpulent; his features were coarse, and his countenance heavy; if not wholly void of animation, it certainly was by no means expressive.
The print of him, from a painting of Mr. Wright, is a good likeness.
In his gait and dress he was rather clumsy and slovenly, and frequently walked with his tongue hanging out of his mouth."
Darwin married twice and had 14 children, including two illegitimate daughters by an employee, and, possibly, at least one further illegitimate daughter.
In 1757 he married Mary (Polly) Howard (1740–1770). They had four sons and one daughter, two of whom (a son and a daughter) died in infancy:
Charles Darwin (1758–1778), uncle of the naturalist
Erasmus Darwin II (1759–1799)
Elizabeth Darwin (1763, survived 4 months)
Robert Waring Darwin (1766–1848), father of the naturalist Charles Darwin
William Alvey Darwin (1767, survived 19 days)
The first Mrs. Darwin died in 1770. A governess, Mary Parker, was hired to look after Robert. By late 1771, employer and employee had become intimately involved and together they had two illegitimate daughters:
Susanna Parker (1772–1856)
Mary Parker Jr (1774–1859)
Susanna and Mary Jr later established a boarding school for girls. In 1782, Mary Sr (the governess) married Joseph Day (1745–1811), a Birmingham merchant, and moved away.
Darwin may have fathered another child, this time with a married woman. A Lucy Swift gave birth in 1771 to a baby, also named Lucy, who was christened a daughter of her mother and William Swift, but there is reason to believe the father was really Darwin. Lucy Jr. married John Hardcastle in Derby in 1792 and their daughter, Mary, married Francis Boott, the physician.
In 1775 Darwin met Elizabeth Pole, daughter of Charles Colyear, 2nd Earl of Portmore, and wife of Colonel Edward Pole (1718–1780); but as she was married, Darwin could only make his feelings known for her through poetry. When Edward Pole died, Darwin married Elizabeth and moved to her home, Radbourne Hall, four miles (6 km) west of Derby. The hall and village are these days known as Radbourne. In 1782, they moved to Full Street, Derby. They had four sons, one of whom died in infancy, and three daughters:
Edward Darwin (1782–1829)
Frances Ann Violetta Darwin (1783–1874), married Samuel Tertius Galton, was the mother of Francis Galton
Emma Georgina Elizabeth Darwin (1784–1818)
Sir Francis Sacheverel Darwin (1786–1859)
John Darwin (1787–1818)
Henry Darwin (1789–1790), died in infancy.
Harriet Darwin (1790–1825), married Admiral Thomas James Maling
Darwin's personal appearance is described in unflattering detail in his Biographical Memoirs, printed by the Monthly Magazine in 1802. Darwin, the description reads, "was of middle stature, in person gross and corpulent; his features were coarse, and his countenance heavy; if not wholly void of animation, it certainly was by no means expressive. The print of him, from a painting of Mr. Wright, is a good likeness. In his gait and dress he was rather clumsy and slovenly, and frequently walked with his tongue hanging out of his mouth."
Erasmus Darwin