Friday, July 03, 2009

Daily sex improves male fertility

The evidence for this seems fairly weak. It would seem to make little difference either way

DAILY sex can improve the genetic quality of a man's sperm and could raise his chances of fathering a child, new research has suggested. Couples who are trying for a baby are often advised to have sex every other day, so that the man's sperm count has time to recover, but scientists in Australia have discovered that this may lower some men's fertility. While abstaining from sex for a few days raises the sperm count, quality can be damaged if a man ejaculates too infrequently.

A study at Sydney IVF, a centre for infertility treatment, has found that daily sex for a seven-day period substantially improves the genetic quality of sperm, without lowering sperm counts enough to impair fertility. David Greening, who led the research, said that for some couples having intercourse every day during the woman's most fertile period could be crucial to starting a family.

The findings, which he presented yesterday at the European Society of Human Reproduction and Embryology conference in Amsterdam, could also have important implications for couples having IVF. Men are usually advised to abstain from ejaculation for three days before providing a sperm sample for fertilising their partner's eggs and many couples do not have regular sex while going through IVF.

When men go without ejaculating, the number of sperm stored in the epididymis at the top of the testicle increases. The longer that sperm sits in the epididymis, however, the more genetic damage it accumulates through exposure to heat and to oxygen free radicals. Dr Greening speculated that daily sex might be more fertile sex. "Through simply clearing the epididymis and testicles, DNA damage has less time to occur. There's less time for vandalism."

Two years ago, Dr Greening conducted a pilot study involving 42 men with high levels of DNA damage in their sperm. It found that daily ejaculation reduced DNA damage levels by 12 per cent. He has repeated the experiment in a larger group of 118 men. Among 81 per cent of men, sperm DNA damage decreased by an average of 12 per cent, though DNA damage increased slightly in the remaining 19 per cent.

Dr Greening said that he had changed his advice to couples accordingly. "If I see a couple and the man has high DNA damage to his sperm, I do the 7-day test to see if it comes down," he said.


Genetic test to produce disease free babies

A “genetic MOT” which can help IVF couples screen embryos for hereditary diseases and have healthy babies could be available in the UK within a year. The technique, known as karyomapping, has the potential to spot virtually any inherited genetic disease. It can also pick up chromosomal problems that might lead to Down’s syndrome or prevent pregnancy. Scientific trials are set to begin on the groundbreaking technique, which has been developed by British researchers and which they believe could eventually even eradicate some inherited conditions like Huntington’s Disease.

But the move will spark fears that the technology is moving towards creating “designer babies”, because it could theoretically be used to screen out non-serious conditions or help couples have babies with “designer” traits such as blue eyes. However, its use would be heavily regulated in Britain and is likely to be limited to extremely serious inherited diseases.

The £2,500 procedure removes the need for geneticists to spend months developing a test for a specific gene mutation, a technique called pre-implantation genetic diagnosis (PGD). Last year the first child in Britain was born free from a breast cancer gene which raises the lifetime chance of developing the disease to 80 per cent, after doctors used PGD. But only around two per cent of 1,500 inherited diseases can be identified in this way.

The new test compares defects in a couples’ genes with that of their embryo, and scientists believe that it can identify almost all known genetic diseases. Developed at the Bridge Centre in London, scientists have successfully proven that the test can identify 100 per cent of embryos with cystic fibrosis, clearing the way for clinical trials to begin later this year.

Gary Harton, from the Genetics & IVF Institute in Fairfax, Virginia, who will lead the trials, said he hoped to be offering the test to tens of couples by December. Embryos proven to be free from the disease are then implanted into the women using in-vitro fertilisation (IVF).

As well as diseases caused by gene mutations the technology can also detect those that come from abnormalities in chromosomes, such as Down’s Syndrome. Detecting problems in chromosomes can also reduce the chance that an embryo will fail to become a successful pregnancy. But the technology will not be able to eradicate most inherited diseases completely, the researchers behind the procedure said.

Professor Alan Handyside, from the London Bridge Fertility Gynaecology and Genetics Centre in London, who pioneered the technology, said it was right that patients should have access to karyomapping. “I believe passionately that it’s a question of patient choice,” he said. “These families know first hand what it’s like to suffer from these conditions. I don’t believe it’s for the Government or scientists and clinicians to debate. “The hope is that clinicians will be able to test embryos for specific genetic diseases and know that, with one test, they are transferring chromosomally normal embryos.” He added: “There are spontaneous mutations happening all the time, but at least now we can identify inherited mutations.”

However, he said that Huntington’s Disease, an incurable brain condition which affects around 8,000 people in Britain could be eventually eradicated because most mutations were inherited.

Prof Tony Rutherford, the chairmen of the British Fertility Centre, said that although the technology did raise the possibility of creating designer babies, those risks already existed because of previous technology such as PGD. He said: “One thing that is superb is that we are regulated (in Britain). The safeguards are there. “We are regulated; we’re not mad Frankensteins working away in our labs creating designer babies. We can only look for major disorders.” He added: “The big advantage of karyomapping is its reliability.”

The announcement was made at the European Society of Human Reproduction and Embryology (ESHRE) conference in Amsterdam.


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