Fertility treatments with clomifene (like Clomid) increases the birth rate of identical twins more than twice. Identical twins are a form of cloning. Does criminilization of reproductive cloning make it criminal to prescribe clomifene based medication?
While twins are 'natural clones', pregnancy with identical twins naturally or as a result of infertility treatment is not a form of reproductive cloning.
Reproductive cloning involves a deliberate biomedical technique - transplanting the nucleus of the donor somatic cell into the host egg cell or reprogramming adult cells into induced pluripotent stem cells ("iPSCs"). Such a clone has one parent - unlike twins who have two parents.
The law I'm aware of pertains to and prohibits the reproductive cloning of human beings.
Article 3(2)(d) of the Charter of Fundamental Rights of the European Union prohibits "the reproductive cloning of human beings."
At the national level, reproductive cloning is banned in EU member states, Switzerland, and many other countries.
Also consider that there are many clinics that openly provide fertility treatment with such drugs, some funded by the public purse (e.g. via the UK's NHS), so either they operate illegally and the authorities turn a blind eye or what they do isn't illegal where they operate.