Medical expenses are deductible if they are to treat a disease or medical condition. For example (at the risk of being indelicate) two women could not deduct the cost of artificial insemination, because being a woman is not a disease or condition. But if part of the cost was hormone treatments to help the woman conceive due to her own infertility, that would be a deductible expense.
Also note that you can only deduct medicL expenses for yourself, a spouse, or a dependent. So if the same sex relationship is not a marriage, you may not be able to deduct expenses you pay for your partner. However, your partner can deduct them as if they paid them, because your payment can be treated as a gift to them.
