Are infertility treatments something you can claim or write off on your taxes?

Nope

If your medical expenses (regardless of what they are) can be written off a certain percentage if they are high enough - ask your accountant to be certain

http://www.irs.gov/taxtopics/page/0,,id%3D16230,00.html

Topic 502 - Medical and Dental Expenses

If you itemize your deductions on Schedule A of Form 1040 (PDF), you may be able to deduct expenses you paid that year for medical care (including dental) for yourself, your spouse, and your dependents. A deduction is allowed only for expenses paid for the prevention or alleviation of a physical or mental defect or illness. Medical care expenses include payments for the diagnosis, cure, mitigation, treatment, or prevention of disease, or treatment affecting any structure or function of the body. The cost of drugs is deductible only for drugs that require a prescription by a physician, except for insulin.

Medical expenses include fees paid to doctors, dentists, surgeons, chiropractors, psychiatrists, psychologists, and Christian Science practitioners. Also included are payments for hospital services, qualified long–term care services, nursing services, and laboratory fees.

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Fertility Enhancement is tax deductable as medical expense.
You can include in medical expenses the cost of the following procedures to overcome an inability to have children.

Procedures such as in vitro fertilization (including temporary storage of eggs or sperm).

Surgery, including an operation to reverse prior surgery that prevented the person operated on from having children.

please check IRS official site for detail,
http://www.irs.gov/publications/p502/ar02.html#d0e1108

However,
You can deduct only the amount of your medical and dental expenses that is more than 7.5% of your adjusted gross income (Form 1040, line 37).

In this publication, the term “7.5% limit” is used to refer to 7.5% of your adjusted gross income. The phrase “subject to the 7.5% limit” is also used. This phrase means that you must subtract 7.5% (.075) of your adjusted gross income from your medical expenses to figure your medical expense deduction.

Example.

Your adjusted gross income is $40,000, 7.5% of which is $3,000. You paid medical expenses of $2,500. You cannot deduct any of your medical expenses because they are not more than 7.5% of your adjusted gross income.

Please check IRS official site,
http://www.irs.gov/publications/p502/ar02.html#d0e2881