INDEPTH: GENETICS AND REPRODUCTION
Timeline: Assisted reproduction and birth control
Owen Wood, CBC News Online | July 24, 2003
July 25, 2003 marks the 25th anniversary (25th birthday, really) of the first test-tube baby. The "miracle baby" was a huge accomplishment in assisted human reproduction. Here's a timeline of that and other feats of science.
Sperm |
1677
Human sperm is discovered by a student of Antonij van Leeuwenhoek.
1827
The ovum (female egg) is discovered by Prussian-Estonian embryologist Dr. Karl Ernst von Baer.
1843
The fact that human conception occurs when the sperm enters the ovum is discovered by physician Martin Berry. This changes the way the world sees human reproduction. While people used to believe that the male implants life into the female, they now know that both the male and female each contribute half the material needed to create life.
March 2, 1873
The U.S. criminalizes birth control, calling contraceptives "obscene material." Canada follows suit in 1882, making it illegal to sell or advertise birth control.
1882
The diaphragm, a plastic or rubber contraceptive device, is invented by German physician Dr. Wilhelm Mensinga.
1914
The term "birth control" is coined by American nurse Margaret Sanger. Using the term resulted in charges against her under the U.S. anti-birth-control laws, through the charges were later dropped.
October 16, 1916
The first birth control clinic in the U.S. is opened by Margaret Sanger in New York, though the clinic is shut down 10 days later. In 1923, she opens the first legal birth control clinic in the U.S.
1920s
Scientists discover that women are fertile about halfway through their menstrual cycle. They therefore conclude that women can avoid getting pregnant by avoiding sex during that period. This becomes known as the "rhythm method." It later becomes the only form of birth control sanctioned by the Vatican, besides abstinence, of course.
1928
The first pregnancy test is developed by German gynecologists Selmar Aschheim and Bernhard Zondek. The test involved injected a woman's urine into a female mouse. If the woman is pregnant, the mouse's ovaries become enlarged and the ovarian follicles mature.
1934
The female hormone progesterone, which is responsible for the cyclical changes in the uterus and is also needed to sustain pregnancy, is isolated by German Adolf Butenandt. For this and other discoveries, Butenandt won the 1939 Nobel Prize in chemistry, which he shared with Leopold Stephen Ruzicka, who also did scientific work with sex hormones.
1934
Gregory Pincus, an assistant professor of physiology at Harvard University, reports that he achieved the in-vitro fertilization of rabbits. Pincus would go on to play a role in developing the birth control pill.
1940s
Chemistry professor Russell Marker develops a way to make progesterone, a process that would be called the "Marker Degradation." The discovery would lead to a number of significant developments in hormone therapies, among them the birth control pill.
DNA |
1953
The three-dimensional, double helix structure of DNA is discovered by Francis Crick, James Watson and Maurice Wilkins. In 1962, the three men were awarded the Nobel Prize in medicine.
1957
The drug Enovid, designed to treat menstrual disorders, is approved in the U.S. by the Food and Drug Administration (FDA). However, the drug also prevents ovulation. Women immediately begin using it as a contraceptive. By late 1959, more than 500,000 American women are using the drug as a birth control pill.
May 11, 1960
The FDA approves the sale of Enovid as a birth control pill. Other birth control pills are soon developed.
Today, condoms are more widely available than they were in the 1960s |
1961
The birth control pill becomes available in Canada. Birth control remains illegal across the country, however doctors prescribe the drug for therapeutic purposes, such as the regulation of the menstrual cycle. Other contraceptives, such as condoms, can be bought at drug stores though they're kept out of sight or disguised to avoid breaking the law.
1961
The drug thalidomide, used to treat symptoms of morning sickness, is found to cause severe birth defects. The children affected, born in the late 1950s and early 1960s, would become known as the "thalidomide babies." The discovery that the drug causes birth defects is made by Australian obstetrician William McBride.
1969
Birth control is legalized in Canada. Abortions are also legalized, though a hospital medical committee must deem the abortion necessary to protect the health of the pregnant woman.
July 25, 1978
The first test-tube baby is born. "Miracle Baby" Louise Brown becomes the first human ever conceived outside of the body when she is born at the Bourn Hall Clinic in Cambridge, England.
Though some attacked the conception as morally wrong, saying doctors were playing God, in-vitro fertilization would go on to help in the birth of more than a million babies in the next 25 years, including Louise Brown's younger sister Natalie. Professor Robert Edwards, who along with Sir Patrick Steptoe oversaw the conception of Brown, recently told The London Daily Telegraph that the moral debate back then was similar to the controversy that now surrounds human cloning.
Robby Reid |
1981
The first fish is cloned. Chinese scientists clone a golden carp.
Dec. 25, 1983
Robby Reid, Canada's first test-tube baby, is born in Vancouver.
1990
The Human Genome Project (HGP) begins. The HGP is the international research effort to determine the DNA sequence of the entire human genome.
1996
The first adult mammal, a female sheep named "Dolly," is cloned. Though Dolly was born in Scotland in 1996, created by scientists at Edinburgh's Roslin Institute, her existence wasn't revealed until February 1997. The accomplishment sparked worldwide discussion and debate as human cloning was no longer an "if" but a "when."
Other mammals that have been cloned since include pigs, goats, mice, monkeys and cows.
Viagra pills |
1998
Viagra becomes available. By 2003, more than 16 million men have used the drug to deal with erectile dysfunction, according to the drug company Pfizer.
September 2000
Genetic techniques used in the creation of Dolly the sheep may one day make it possible for two men to conceive a child, says Dr. Calum MacKellar, a lecturer in bioethics and biochemistry at the University of Edinburgh. MacKellar says the process would still need a woman's egg and a surrogate mother, but a child could be made by combining the DNA of both fathers.
The process would use nuclear replacement techniques to make a so-called "male egg." The egg would be created by removing the nucleus from a donor egg and replacing it with the nucleus from a sperm cell. It would then be fertilized in-vitro by another sperm before being implanted inside the surrogate mother's womb. However, the embryo of a mammal created using only paternal DNA would lack the genes that allow embryos to develop normally – an obstacle scientists would need to overcome.
November 25, 2001
The first cloned human embryos are created. Advanced Cell Technology, a privately funded company in Massachusetts, makes the announcement, saying it was not attempting to create a human being, but trying to develop a source of stem cells to be used to treat degenerative diseases.
Other research groups have made similar claims, but Advanced Cell Technology is the first group to do so that has a respected track record in the use of reproductive technologies. In December 1998, scientists at Kyeonghee University in South Korea announced they had produced the world's first cloned human embryo, however the work was not published in a scientific journal and many researchers around the world doubt the experiment ever took place.
Dolly |
February 2003
Dolly the sheep is euthanized after developing premature arthritis and progressive lung disease. Researchers have found that cloned mammals often develop genetic abnormalities. In the case of six-year-old Dolly, the sheep aged faster than normal – sheep usually live to be about twice her age.
April 2003
The Human Genome Project is completed.
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In vitro fertilization
In June 2000, the Canadian Fertility and Andrology Society (CFAS) released the first nation-wide collection of data on assisted reproduction. Seventeen of the 20 centres in Canada that offer in vitro fertilization voluntarily submitted information for the study. Here are some of the results:
in 1999, 4,290 in vitro fertilization cycles were started in Canada.
of those, the overall pregnancy rate was 26 per cent.
complications occurred in less than three per cent of cycles.
one-third of the pregnancies were multiple births, most of which were twins.
a women's age has a strong influence on pregnancy rate. The pregnancy rate was 32 per cent for women under 35 years old, 26 per cent for the 35 to 39 age group, and 13 per cent for women over 40.
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