I am a young, white, tan, female and I have noticed that my stomach has become discolored. It is almost spotted-looking. Is this the side effect from birth control pills, or does it sound like a more serious problem?

I am not actually worried but simply curious. When petting with my boyfriend and getting in contact with his sperm, my skin turns slightly red where his cum touches me. Am I allergic, or is there perhaps any other explanation? I am 24 years old and female.

I use Nalgene bottles for about 75 percent of the water I drink each day. Therefore, I was startled to find out that there is some possibility that these bottles leach chemicals into the water. I've found conflicting opinions about the veracity of these claims on the Internet. What's the truth? Should I dump my Nalgene for glass? You have an earlier post about bottled water, but it doesn't seem to address this issue specifically, and you recommend purchasing reusable bottles like the ones that might be poisoning me. The bottles I use have #7 on the bottom in the recycle symbol.

1) Which is better for you, tap or bottled water?

2) How bad is the water here in New York City? Do you recommend drinking filtered water, or does it really make a difference?

Why is your favorite food very tasteless when you have a cold?

Recently I bought a sun protection cream from a health food store. The cream claims to provide sun protection (it's labeled SPF 15) by a plant complex made of PABA, willow bark extract, myrtle and myrtus leaf extract. It says that myrtle and myrtus leaf help protect from both UVA and UVB.

My questions are as follows:

1) Can this PABA complex provide the sun protection it claims (SPF 15 for both UVA and UVB rays)? The reason I am asking this is because until now I had only heard of sun protection by titanium dioxide or chemicals like octyl mexaoxycinnamate (did I get it right?). So I am curious to find out.

2) I notice a slight burning sensation in my eyes after I apply the product on my face. Is it true that PABA is a common irritant? (Since I notice many products proudly claiming PABA-free I wonder if it's really not good for you.)

Please help. I hope this question falls within your realm of expertise. After all, you are the 'know it all' around here, aren't you?