You have to pick:

By what means?
Magic? Me? Random guys?
As long as it's not the middle one, I'm fine with this.

I'm thinking its magic but you would show up as the father in the paternity test.

Is this like an aura of pregnancy or a one time thing?

Permanent aura

If it's by magic, then would they still get pregnant if they physically can't?

awkward when you visit your family

It occurs to me that this doesn't limit the effect to *human* females.

Those paternity tests could potentially become extremely embarrassing. And many interesting hybrids would ensue.

I think (and hope) it means human females.

Hm. Global earthquakes as the ground shifts and settles, and places with ground level near the 100m mark will probably get fissures spewing high-pressure liquefied whale from them. That's kind of nasty. But I wouldn't be surprised if most of the whale goo remains sequestered deep underground in the high-altitude regions and becomes a new sort of "fossil fuel" resource to tap into.

Ten years gives a lot of time to earthquake-proof our infrastructure, though it'll still really suck. Not as bad as most of the other world-affecting whale WYRs.