Freedom of wombs
Freedom of wombs (Spanish Libertad de vientres), also referred to as free birth, was a judicial principle applied in several countries in South America in the 19th century; it freed slaves' children at birth, rather than having them become the property of the parents' owners. Although intended to be a gradual abolition of slavery, the principle was unevenly applied and many countries did not follow through with full abolition.
A movement for independence from Spain grew in the American colonies in the 19th century, influenced by liberal ideas, such as the abolition of slavery, which Mexico had declared in 1829 by President Vicente Guerrero, Great Britain in 1833, and the United States in 1865 at the end of that country's civil war. One of the first steps in gradual abolition was the Ley de Libertad de Vientres, an 1811 law written by Manuel de Salas of Chile.
In Argentina, the Law of Wombs was passed on February 2, 1813 by the Assembly of Year XIII. The law stated that those born to slave mothers after January 31, 1813 would be granted freedom when contracting matrimony, or on their 16th birthday for women and 20th for men. Upon manumission, they were to be given land and tools to work it. In 1853, Argentina fully abolished slavery.
Spain passed a similar law in 1869 to apply to its plantation colonies of Cuba and Puerto Rico, and passed it in 1870, to take effect in 1872. On the Iberian mainland, Spain had abolished slavery in 1837. It is also known as Ley Moret (Moret Law). 
The countries that first freed the children born to slave mothers proceeded to abolish slavery in total later. Similar gradual abolition laws had been passed in some of the northern United States after the American Revolutionary War, namely, New York in 1799 and New Jersey in 1804. All the slaves were freed in both states before the American Civil War.
- "Manuel de Salas" (Spanish)
- "Pasado y presente de los Negros en Buenos Aires" (Spanish)
- "La sociedad a inicios de la República" (Spanish)
- "http://www.colombiaaprende.edu.co/html/etnias/1604/article-82844.html" (Spanish)
- "La Ley de Vientres Libres y los intereses esclavistas" (Spanish)
- "Ley de Abolición de la Esclavitud" (Spanish)
- "REFORMAS ECONÓMICAS DE MEDIADOS DEL SIGLO XIX" (Spanish)
- "Instrumentos Nacionales de Derechos Humanos" (Spanish)
- "De la Independencia a nuestros días" (Spanish)
- "LEI DO VENTRE LIVRE" (Portuguese)