Hypothetical situation: A Catholic husband and wife are validly married. The husband has a genetic disease. Is the following method of procreation immoral?

1) Find a male without a genetic disease. Let’s say they pick a mathematician.

2) Using two syringes, physically replace the husband’s sperm with the mathematician’s sperm.

3) Husband and wife engage in conjugal act.

4) The offspring has the mathematician’s and wife’s DNA.