• Question: how do you test how smoking,excersise and weight and diet effedt the sperm function

    Asked by to Divya, Clare on 14 Mar 2014. This question was also asked by .
    • Photo: Divya Venkatesh

      Divya Venkatesh answered on 14 Mar 2014:

      I think you meant this for Clare who is the expert on this. But I’ll try — I think most of these experiments work by comparing a set number of people — for example you could have a group that doesn’t smoke and one group that does and then you test the sperm function in the lab for each and see if one group does better than the other. You try and control for all other factors that might affect the result such as age of the men in the two groups should be the same on average, comparable lifestyles etc.

      I’m sure Clare will be able to add/correct me if I’m wrong so do ask her!

    • Photo: Clare Nevin

      Clare Nevin answered on 15 Mar 2014:

      Like Divya said, we get volunteers to donate their semen, and we either separate them into groups based on a certain factor. So smokers and non-smokers; obese people and people of normal weight; athletes and non-athletes; and old and young people. You always compare your ‘test’ group to a healthy control group.

      Once we have detailed information on people’s lifestyles, we analyse the following parameters:

      1) Sperm concentration in each sample – so the number of sperm cells per millileter of semen
      2) Sperm motility – using a wet preparation of semen under the microscope, I count the number of fast, slow and immotile sperm cells
      3) Sperm morphology – the shape and size and structure of the cell which should have an oval shaped head piece, a midpeace and a straight tail.

      I then extract the sperm DNA and RNA and analyse expression of genes that are important in fertility.

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